There were two minor megatons over at the official Windows blog this weekend; first, Microsoft confirmed that the new-and-improved, Release Candidate version of Windows 7 will become freely available to the public next Tuesday, the 5th of May.

The list of improvements over the beta release that was free a few months ago is long, and we only barely touched the surface when we first got the list, but among the changes are some new user interface features, like integration of Aero Peek (which hides unused windows) into the Alt Tab menu.

Perhaps even more exciting (for some folks) is the announcement of XP Mode. It won't be in the RC  next week, but it will become available sometime soon. With it, you'll be able to run old programs designed for Windows XP that haven't worked in Vista or 7 before. It actually runs a virtualized Windows XP in the background, seamlessly integrating legacy programs into Windows 7.

It'll be a free download for the RC version of Windows 7 (and later for the post-release Professional and Ultimate versions), but Microsoft hasn't said exactly when it'll become available. It should help Windows 7 find more popularity than Vista did with businesses that rely on old software, and that could be huge.