- ManyBooks - Free eBooks for your PDA, iPod, or eBook reader - Thanks Tony Bryan & abben
- BookCrossing - Where real books are released into the wild to be found by others - Thanks Engtech
- LibraryElf - The perfect companion to a public library system - Thanks Engtech
- Scribd - Open library to publish and discover documents online - Thanks CincauHangus
- Word Public Library - 400,000 PDF ebooks for download - Thanks Ellen
- Free Tech Books - Free computer science and engineering books (+ lecture notes) - Thanks Ellen
- Bookins - Swap real books with other readers - Thanks Jimbob
- WellToldTales - Free short story podcasts (like audiobooks, but shorter) - Thanks Kevin C.
- Wowio - Public domain, free legitimate copyrighted materials & one of the only with a selection of Comic Books - Thanks Jane and Art Dardia
- BizBooktalk - Free book giveaway contests on Fridays - Thanks Brandon
- MoochMuch - Organize your book lending with your friends - Thanks Bobby
- CHMPDF - A collection of general interest and technical ebooks - Thanks Manish Garg & Brian Di Croce
- Realtime Publishers - free IT eBooks by many of the world’s best authors - Thanks Kevin
- FrugalReader - Trade Books for free - Thanks Brent
- TitleTrader - Swap books, movies, and music - Thanks Brent
- ZunaFish - Trade your old media and books items for new titles you’d rather have - Thanks Brent
- SwapSimple - Swap your used books here - Thanks Brent
- SwapThing - Community of users who swap items including books - Thanks Brent
- BookCart - Internet paperback exchange - Thanks Brent
- SF-Books - Exchange Sci-Fi Books here - Thanks Brent
- PaperbackSwap - Swap books for free - Thanks jane dough, IBelieveInFairies, & Lauren
- PinkMonkey - 450 Study Guides / Booknotes / Online Chapter Summary Notes and Analysis - Thanks Spellchecker
- eBookWorld - Technical resources - Thanks 5n7p3r
- Flaxx - IT and computer books - Thanks tejinder
- Baen Library - Free science fiction and fantasy novels - Thanks lanthus & Glen Davis
- LibraryThing - Social networking and free books - Thanks Michael
- Online Books Page - Facilitates access to books that are freely readable over the Internet - Thanks Aman
- Podiobooks - free audiobooks that you can subscribe to with iTunes or any other podcatcher - Thanks KJToo
- BookRags - Research material in the form of eBooks - Thanks Henry Delany
- Technical Books Online - Old tech books from the “vacuum tube age” of electronics- Thanks obiewiz
- ebookSearchr - Google powered Thanks Rico & Rokker
- Internet Archive - The Intenet indexed - that includes a vast text library - Thanks jojo
- BookYards - Books, videos, education materials- Thanks Victor
- Memoware - Free books for your PDA - Thanks Doug
Original Top 10 list with full reviews (here and here)
- Gutenberg Project Top 100 - Popular books from the oldest producer of free ebooks on the Internet
- BookMooch - Community for exchanging used books
- ebookSpyder - Specializes in technical books ranging anywhere from C# to AJAX
- Google Book Search - Read the classics online
- Dwalin - plain text novels
- Free Computer Books - Technical resources about computers
- Librivox - Audio works and podcasts of books
- CliffsNotes - Get the notes to cram for the exam
- WIkibooks - Free textbooks
- DailyLit - Receive small parts of books via email
