Talking Books Program
The Talking Books Program is part of the Library of Congress' National Library Service for the Blind and Physically Handicapped (NLS). Persons who are blind and visually/physically impaired may qualify for free books through this program. Persons with reading disabilities may also qualify in certain cases. Materials are shipped postage free using the Free Matter for the Blind and Physically Handicapped Mail.
Talking Books are currently available in four-track cassette format. However, NLS is beginning a new digital download pilot project for books. 
Persons interested in learning about more library related resources for visually impaired or physically handicapped inviduals can visit various internet related blogs on the topics. An example of such a blog is one written by the Talking Books Librarian.