With variable MP3 pricing the new norm as major online music retailers across the board bowed to aggressive licensing renegotiations from the major labels (effectively making hit singles and popular music more expensive), it's a great time to look at some of the alternatives to the usual suspects (iTunes, Amazon, Wal-Mart, et al) out there for discovering, streaming and downloading new music on the cheap and even, in many cases, for free. 

We've broken the following list into a few major buckets (free downloads, curated sites, recommendation engines, search engines, social music sites/services, and subscription or other services that offer pricing alternatives to mainstream MP3 retailers) but there's certainly some overlap amongst the sites listed below. Specifically internet radio sites are so numerous as to deserve their own separate mega list, so we've tabled sites like Live365 and ShoutCast for now and focused more on services that offered more than just radio streams. We also omitted pure mixtape services and some of the extremely tiny and/or possibly deadpooled music sites — if we missed your favorite or feel we've miscategorized anything, please let us know in the comments and we'll keep revising the list.

Free downloads

With many tracks available for free under the excellent Creative Commons license — with some available for remixing as well — you'll find some excellent free tunes in this category. Although most of the following sites are focused on independent and unsigned acts, you'll find some free gems from known and signed artists here as well.

• AltSounds -- alternative online music community offering streams and downloads from independent artists.

• Broadjam -- a music community primarily designed to help independent musicians network, promote their wares and score licensing deals, Broadjam also offers a library of free and paid streams and downloads from over 93,000 artists and bands.

• bt.etree.org -- free downloads via BitTorrent of concert recordings by trade friendly artists and bands.

• ccMixter -- community music site sponsored by Creative Commons, featuring a collection of freely downloadable and remixable CC-licensed tracks and remixes, including sample packs and a cappella separated tracks.

• Classic Cat -- aggregate collection of specifically classical music MP3s available for free download. Search or browse by composer, performer, instrument, etc.

• dmusic -- indie music community offering free downloads and streams of mostly unsigned artists and bands.

• EZ-Tracks -- offers free MP3 downloads from some major label artists thanks to partnerships with the labels.

• Free Kids Music -- large collection of free MP3 downloads of music for the younguns.

• GarageBand -- owned by iLike, this separate site offers free streams and free and paid MP3 downloads from mostly independent artists.

• Honc -- free streams and downloads from mostly unsigned and independent acts.

• iCompositions -- an online artist community with a specific focus on Macintosh-produced music and, even more specifically, tracks composed in Apple's GarageBand software. Free streams and downloads available.

• Internet Archive -- a veritable treasure trove of freely available audio (as well as video), the Internet Archive houses various collections including the Live Music Archive of concerts in lossless format, a Music collection featuring downloads from netlabels, contemporary performances and a unique 78 RPM collection, an Open Source audio collection, and a downloadable Radio collection.

• iSound -- offers a large catalogue of free downloads and streams from independent and some signed bands.

• Jamendo -- community of free and legal music available for streaming and download

• Magnatune -- free downloads have DJ announcements, or pay a monthly fee to download original source tracks in multiple formats. All tunes are free to remix for non-commercial purposes, or available to license for use in commercial projects.

• Mac Idol -- large collection of freely available MP3s by mostly independent artists with a focus on acts producing music on the Mac.

• MTV -- it's only a small collection with each subset available for a limited time, but it's worth hitting up now and then for music lovers looking for freebies from top artists.

• Muzic -- collection of freely-available MP3s from indie and unsigned artists. Sister site MP34U offers a curated list of best free tracks from around the web.

• Newgrounds -- Offers a collection of free streams and downloads submitted by artists under various licenses.

• Opsound -- dubbed a "gift economy in action," Opsound is an experimental site inviting artists to upload tracks under Creative Commons licenses for others to listen, share, and remix.

• Project Opus -- dedicated to supporting and promoting local and independent music, Project Opus offers a catalogue of free streams with a subset available for free download (and others available for purchase).

• SoundClick -- free streams and downloads from mostly unsigned and independent acts.

• Stereokiller -- independent music community with a focus on hardcore, emo, metal and hip-hop. Free streams and downloads available.

• Unsigned Band Web -- more free streams and downloads from mostly unsigned and independent acts.

Curated sites

These sites offer legal music chosen by knowledgeable editors and music lovers. Some offer streaming only, some downloads, and some a mix of both. This is by no means a comprehensive list of all the great music blogs out there — if we didn't include your favorite, let us know in the comments and we'll add it to the list.

• 3hive -- extensive MP3 blog curating links to free and legal MP3s published on official label and artists websites.

• betterPropaganda -- an "interactive, multimedia music magazine" showcasing a range of artists from independent and major labels since 2003. Features original content plus streams and downloads.

• Blentwell -- daily linklog of mostly full-length DJ sets in MP3 format.

• Epitonic -- combining the "best features of a college radio station and an independent music magazine," Epitonic offers original content alongside streams and downloads. The Echospin store offers select whole albums for sale.

• Free Albums -- music blog with reviews of full albums available for free download from various sources.

• Free Music Archive -- beta social music website built around a "curated library of free, legal audio." Curated by a number of partners including radio stations, webcasters, netlabels and other online music collectives.

• Indie Rock Cafe -- offers free streams of curated playlists posted blog-style.

• MOG -- a curated clearinghouse of over 5,000 music blog posts a week, edited into a digestible daily destination for music lovers; "as dynamic and rich as a site like the Huffington Post, but completely devoted to music."

• MP3.com -- part curated site with news and features, part repository for mainstream and independent artists alike, MP3.com is part of the CNet family and offers many free streams and downloads.

• New Musical Order -- music blog dedicated to providing links to the best free and legal music downloads on the web.

• NPR Music Downloads -- Public radio clearinghouse of song, podcast, live session and concert downloads.

• PureVolume -- curated social destination site for the discovery and promotion of new music and emerging bands.

• RCRD LBL -- network of mostly independent labels and blogs offering downloads and other content curated by editors and partners, started by Engadget founder Peter Rojas.

• Stereogum -- long-running music and MP3 blog with extensive archives of free downloads and streams.

• The Fader -- music and style-focused companion to The Fader Magazine, free track downloads from up-and-coming and popular new artists are posted blog-style.

• The Hype Machine -- the Hype Machine curates and aggregates a number of hand-picked MP3 blogs and serves up the best MP3s, streams and discussions surrounding new music.

• we7 -- This site offers a number of free and legal full streams, although a sizeable subset are only 30 second previews. Curated recommendations, charts and features aid in music discovery, and members can set up playlists that can be streamed via the persistent player, uninterrupted by new page loads.

Recommendation and discovery engines

The goal of this group of sites is to help steer you toward new music you might like based on music you already do like. Services in this category use a mixture of algorithmic, social, and user behavior analytic methods to find similar music based on traits, recommendations and other inputs.

• last.fm -- social music site last.fm helps discover new music based on music and genre tags you already like. Add explicit tags or artists to get recommendations on or scrobble tracks to build a profile and get recommendations based on what you listen to. Add friends to your social graph and get recommendations directly from them as well as based on what they listen to.

• Pandora -- Where last.fm takes the social, crowd-sourced approach to music recommendations, Pandora taps into the extensive Music Genome Project to provide a more "scientific" approach to recommendations. The database stores various attributes of artists, albums and tracks and pulls out similar characteristics in new tracks to play for you. Train the system with your likes and dislikes and create stored playlists or "stations" for easy access later.

• Audiobaba -- Pandora and last.fm are the two reigning giants in this space, but some other contenders are certainly worth checking out. Audiobaba takes an algorithmic approach to acoustic matching to recommend similar sounding tracks to songs and artists you like. Users rate the supplied matches for accuracy, and the feedback gets fed back into the artificial intelligence-based recommendation system.

• finetune -- A very clean and simply designed interface is the gateway to a recommendation meets social tagging meets personalized radio service; finetune is a bit like a hybrid between Pandora and last.fm, drawing on a collected database of 7 years' worth of listening behavior to provide recommendations whilst incorporating user tagging and some editorially-driven playlisting. A companion iPhone application integrates with the web site.

• mufin -- Mufin takes a similar approach to Pandora in that it analyzes the attributes and elements of specific tracks -- but instead of using the human expert-curated Music Genome Project the site uses an automated algorithm to analyze aspects of songs such as rhythm, tempo, and instrumentation and suggest similar tracks based on shared musical properties. Listen and discover in the web-based player, use the free mufin player or integrate with iTunes or your browser.

• musicmesh -- unique and simple interface allows you to search for an artist/album/track and find a match displayed visually mind-map style with 6 related or similar albums. Click on any album to get a track list, and click a track to play any associated YouTube videos of the song.

• musicovery -- This site takes a unique visual approach to music discovery, prompting you to input listening criteria (genre, year, mood, tempo, etc.) and presenting a visual, mind-map style array of search results that fit the attributes described. Songs are streamed in lo-fi quality, with paid subscriptions offering more features and hi-fi audio.

• StumbleAudio -- StumbleAudio is not affiliated with bookmark discovery site StumbleUpon in any way, but the concept is similar. Choose a genre to start listening to, feed likes or dislikes into the system and get better recommendations. Click the "stumble" button to get another suggestion. The selection is focused on independent and unsigned acts, with links to purchase from the major retailers if desired.

Search engines

The primary focus of this group is to index and return matching audio file results on user queries for artist, album, or track.

• midomi -- offering text-based search and stream like most in this category provide, midomi offers a unique extra feature in the ability to sing or hum a part of a track and determine what song it is. For iPhone users there's also an associated mobile app that offers the surprisingly accurate audio search functionality.

• MP3 Raid -- search, stream and download audio tracks indexed from around the web.

• SeeqPod -- indexes publically accessible MP3 files from around the internet for search and streaming. Perpetually financially-troubled, this music search engine may or may not be serving tunes by the time you read this...

• SkreemR -- Like others in this class, SkreemR indexes publically accessible MP3 files from around the internet and provides a search and stream user interface to locate and play tunes.

• Songza -- simple search and playback via a simple-to-use UI sets this music search engine apart from the pack. When clicking a found track's name, a unique "pie menu" display allows you to play, share, rate, or add the track to your playlist. If a returned result is hosted on YouTube, the video plays in the right-hand sidebar along with the audio.

Social music sharing sites and streaming services

The distinction between this category and the "curated" section above isn't entirely hard and fast — you'll find some curated sections on these sites and some social services on the above. But for the most part the following destinations have a primarily social component to sharing music and artists both old and new.

• babulous -- free streaming tracks and albums from mostly independent artists, with an upload feature to add your own MP3s and social features including Myspace and Facebook integration.

• blip.fm -- Twitter-like real-time music sharing site where member DJs search for and play tracks; liking another DJ's track gives them "props," a site currency members can use to give props back to other DJs and tracks they like.

• Deezer -- legal streaming site with major partnerships in place and a catalogue of about 2.5 million mainstream and independent tracks, this French startup offers easy free search and streaming with community and social features.

• Free Napster -- you're limited to three free plays of any track and only 25 free streams per month, but if you have the occasional mainstream selection itch to scratch you can find it on this free hub provided by the subscription service. The site will generate "Napsterlink"s to tracks or artists you want to share with friends.

• Grooveshark -- The site features easy search and playlist building features alongside social sharing and discovery. You can upload your own tracks to add your collection if they're not already offered on the site.

• Hypster -- similar to Project Playlist (below), Hypster's focus is on helping you quickly build playlists for embedding and sharing on Facebook, Myspace, your blog, etc. A search engine pulls in indexed MP3s or you can upload your own tracks.

• iLike -- a number of social and discovery tools are available on the website, or install the optional iTunes or Media Player plug-in for even greater integration. Get recommendations and notifications of gigs by your favorite artists as well as local gigs in your area, a handy differentiating feature for this service that also integrates with Facebook and other social networks.

• imeem -- social music and networking service built around the sharing of digital media, with a particular focus on music and music videos. Users can access, rate, tag, and comment on music, videos, photos, polls and blog posts from other users. Media playlists are a prominent feature of the site, wherein content from various sources can be pulled together into a single playlist that can then be published and made open to comments and ratings.

• Jango -- Part recommendation and discovery engine, part custom radio stations and part social sharing, Jango lets you set up stations based on an artist or song search, rate tracks, view lyrics, share playlists and purchase tunes from major retailers. The service is free and ad-supported, although the interstitial video ads interrupting your audio stream can be rather intrusive.

• Lala -- While Lala also offers MP3 downloads at major retail prices, they also offer a $0.10 web-only streaming plan for any song in their 6 million track library, with 50 free starter tracks. Via their custom Music Mover software, you can also synchronize any matching tracks from your local collection to your Lala collection, effectively rendering your music collection streamable from any web browser. Social features allow member following/friending and social-based recommendations.

• Myspace Music -- the music-centric service arm of the social networking site, Myspace Music provides instant streaming access to millions of major label and obscure tracks and music videos, with the ability to create your own playlists and listen to popular playlists created by editors and other users. You'll have to put up with an advertising extravaganza, but all the services are free.

• MyStrands -- part music recommendation engine, part social music service, MyStrands is a free desktop application plugging users into social and discovery tools.

• Project Playlist -- this site's focus is on easy playlist building with a quick path to embedding your playlists on your blog, Facebook, Myspace or other sites. Search the collected internet index of MP3s and quickly drop them into shareable playlists.

• SoundPedia -- focuses on creating personalized radio stations based on similar artists and genres. You can manage your created stations by rating the songs in the stream and share your station with other users.

• Spotify -- currently in closed beta mode and available only to parts of Western Europe at the moment, Spotify is nevertheless an up-and-coming search and streaming service. Paid monthly streaming subscriptions will be available in almost all countries after the full official launch.

• The Sixty One -- social music community where independent and unsigned artists can upload tracks for review by the users. Tools and badges aid in music discovery and recommendation, with users earning reputation for voting up tracks that become popular.

• tunesBag -- similar to Lala in allowing you to upload your own music collection and stream or share it in a web browser, tunesBag is an Austria-baed startup currently in closed beta.

Subscription downloads and paid services

A la carte pricing as set by the RIAA isn't the only game in town. Here are a handful of paid alternatives to iTunes/Amazon pricing, including several flavors of subscription and a unique twist on an MP3 pricing economy from Amie Street.

• Amie Street -- The Amie Street catalogue of more than a million tracks is priced between free and 98 cents per track depending on the internal economy of Amie St. downloaders (more downloads = more popular, driving the price upward), offering a decent alternative to major digital retail pricing with a reasonable selection to choose from. Streamed previews of about a minute per track are also available, and a recommendation engine can help lead you to tracks and albums you might like based on artists you already know.

• Audio Lunchbox -- online music store focusing on independent artists. Offers over two million DRM-free licensed tracks for sale and download either a la carte or via several subscription plans.

• eMusic -- extensive selection of over five million DRM-free MP3 tracks from 60,000 record labels, available for download via reasonable monthly subscription plans. Extensive database of high-quality editorial and recommendations based on taste; useful social tools including member playlists (I've been a member of eMusic for several years under an awesome 90 downloads for $19.95 plan -- great value, great selection -- Barb)

• Napster -- Yep, still around. Subscription music services don't seem to be everyone's bag, but if you enjoy buffet-style all-you-can-eat access to huge swaths of new music at your fingertips like we do, Napster provides a reasonable service starting at $12.95 per month. Like major competitor Rhapsody, Napster offers a Napster To Go plan for taking music with you on your portable device (including some supported phones) as long as it's not a certain player, and MP3 downloads at major retail prices for those tracks and albums you really want to own.

• Rhapsody -- Rhapsody has the distinction of being in both categories of "major retailer" and "alternative" thanks to its subscription plans. Although the site does offer a la carte and album MP3 purchases, they're hit with the same "filler tax" iTunes, Amazon et al are facing. However, their monthly all-you-can-eat subscription plans are still reasonable at $12.99 for web-based and $14.99 for portable Rhapsody to Go services.