1.Gutenberg project Top 100 list: 

This site is the oldest producer of free ebooks on the Internet.  Their collection, pieced together by thousands of volunteers, now amount to over 20,000 works which have fallen into public domain.  With great numbers however, comes the headache of picking true literary gems from the fodder -  That’s why this Top 100 page is so valuable.

 

2. Exchange Used Books With BookMooch

Want a real physical book for a change?  BookMooch is a community for exchanging used books.  Under a points system, it lets you give away books you no longer need in exchange for books you really want.

3.Get Technical Books With ebookspyder

This site specializes in technical books ranging anywhere from C# to AJAX.  Many commercial works can be found here though.  This makes the legality of this particular site questionable… but we of course assume you own these books before you download them :)

4. Read the Classics Online with Google Book Search

This service has been giving Google a fair bit of copyright headaches, but has moved forward quite well in spite of the circumstances.  It comes with a book-like interface which many people like – I am unfortunately not one of them.  Maybe it’s just me, but I like to download my books rather than read it of a website. If you’re going to use this service, select ‘full view books’ under the options page for best effect

5. Download Plain Text Novels With Dwalin

This is as basic as it gets, and consists of an open directory with plain text files for download.  Don’t be fooled.  Their library is comprehensive, and plain text would be the most portable file format around.