Despite all the great ideas we come up with, we're always hearing people warning us not to quit our day jobs. For one lucky programmer, a surprise iPhone App Store hit has actually enabled him to do just that, after earning over $600,000 from just one month of sales alone.

Ethan Nicholas wrote iShoot in his spare time after work, releasing the game last fall. It's a simple tank game, similar in gameplay to to the titles in the Worms series of PC games. Though he saw only slow sales at first, after releasing a "lite" version of the game as a free download, sales for the full, three-dollar version started to pick up. Last month the title reached the number one spot in the App Store and managed to hold it for twenty-six days.

We're really enamored with a business model like Apple uses, that lets even unaffiliated programmers put together a pet project in their spare time, and have the very real potential to become millionaires as a result. There's no word yet on if Nicholas is planning a follow-up project, or if he's content to enjoy the iShoot spotlight for a while longer. This fame and fortune have hit him quite suddenly; he hasn't even gotten his monthly payment from Apple since the game took off, thought we're sure that's one check he'll be waiting for by the mailbox quite eagerly.

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