Freeload Press - free as in beer, not as in speech (with registration + survey)...Textbooks and study aids available at the Freeload Press site are designed for use in college courses, advanced placement high school courses and for professional reference.

Free Non-business Textbooks..Internet Library...variety of subject areas

Open Text Book is a registry of textbooks and text book material that is open in accordance with the Open Knowledge Definition (OKD). It is run by the Open Knowledge Foundation.

RHL School - Free Teaching Resources: Your place to get an enormous supply of free quality worksheets for teaching, reinforcement, and review. Free worksheets that are truly unique! Many of these worksheets can serve as the basis for lessons.
School Express - Our mission, is first to furnish free products to the educators throughout the world. Educators in many countries are accessing our free worksheets and software.

Textbook Revolution is the web’s source for free educational materials. This is a student-run, volunteer-operated website started in response to the textbook industry’s constant drive to maximize profits instead of educational value.

Wikibooks is a Wikimedia community for creating a free library of educational textbooks that anyone can edit. Wikibooks began on July 10, 2003, since than Wikibooks has grown to include over 32,580 pages in a multitude of textbooks created by volunteers