Bookshare is the world's largest online library of accessible e-books for people with print disabilities. It is free for U.S. students who have a qualifying print disability. www.bookshare.org
Learning Ally is a national non-profit dedicated to helping students with print disabilities, including blindness, visual impairment and dyslexia. Learning Ally improves the way students learn at home and in the classroom. www.learningally.org
American Printing House for the Blind produces textbooks in Braille and large type, educational tools such as braille typewriters and microcomputer software and hardware, teaching aides such as tests, performance measures and other special supplies.
http://www.accesstext.org/resources.php
Colorado Talking Book Library CTBL provides audio, Braille and large print books free of charge. https://myctbl.cde.state.co.us
Rocky Mountain Branch of the International Dyslexia Association http://idarmb.org
The Accessible Textbook Finder helps you search various vendors to find accessible titles. Each vendor has their own policies and accessibility features.