Math for hackers.
profquail: Instead of starting your own, why not contribute to Wikibooks? It's already an established site with a fair number of users, but there are several sections (especially technical areas) that are incomplete or haven't been updated in years. Plus, everyone else would be able to start contributing NOW.http://en.wikibooks.org/wiki/Wikibooks:Mathematics_bookshelfhttp://en.wikibooks.org/wiki/Wikibooks:Computer_science_book...