One of my favorite places to go for free ebook downloads is the Internet Archive. This site has not only free and legal downloads, but also offers free videos and songs. The best thing is, you don't have to worry about copyright issues. If it's on Internet Archive, you can download it legally. If something is up there and shouldn't be, the administrators pull it off right away. It's a fabulous source for books, and has quite a few titles that you can't find on Project Gutenberg.