Big list of free book sites here!
http://www.friedbeef.com/2007/04/09/...ltimate-guide/
Cheers
Editor's Note: Thanks to realityloop for the link. This is the second time I've seen this link pointed to, so I suppose it deserves front page visibility. I haven't checked out the links, so of course be considerate of copyright law and general safe computing practices as you look through the sources.