Digital+Textbooks

Connextions http://cnx.org/

Free Textbooks Search http://www.freetextbooks.eu/

Wikibooks http://en.wikibooks.org/wiki/Main_Page

The Assayer http://www.theassayer.org/

Collections of books that are freely available include [|Project Gutenberg], Read Print, Bartleby, Online Books, Electronic Text Service, and the Open Book Project.