23K+ Free Kindle Books at munseys.com
Another good place to download free books for your Amazon Kindle is http://www.munseys.com/. Main website itself is a bit heavy for Kindle Basic Web to render so you can use section of the website that is specifically optimized for mobile browsing: http://www.munseys.com/joomla/. There you can browse books by category. Within categories you can search. Unfortunately you can’t search all of the categories at once and you can only search by book title.
Still it’s a very nice place to get books. Books are in Mobipocket PRC format and most have usable table of contents. As of 3/1/2009 munseys.com boasts 23,853 books in it’s collection.