addall.com
The book search engine that allows you to comparison shop more than 40 online bookstores including Amazon, Barnes and Noble, and Borders.
LINK: http://www.addall.com/
books.google.com
Google Book Search the power of Google to find books. It is a tool from Google that searches the full text of books.
gutenberg.org/
Project Gutenberg is a library of over 60,000 free eBooks. Chose among free epub and Kindle eBooks, download them or read them online.