1. Google Books

google.com

2. Project Gutenberg

gutenberg.org

3. Internet Archive

archive.org

4. Open Library

openlibrary.org

5. Smashwords

smashwords.com

6. Blurb

blurb.com

7. Scribd

scribd.com

8. Wattpad

wattpad.com

9. 24Symbols

24symbols.com

10. Books In My Phone

booksinmyphone.com