"This is a listing of 27 sites that legally offer free textbooks and written course material.
There is a separate page with links to free audio and video courses.
To the best of my knowledge all of the websites listed here offer only content that they are legally entitled to transfer to you. If you find a site listed here that you know illegally offers copyrighted material, please contact me through the site with a link to the infringing content."
Via Beth Dichter, TechinBiz
If you are looking for sources of free textbooks this post may help you find them. Thre are 14 new sites included in this list. Textbooks are available in many disciplines and grade levels, from elementary school through college.