Note from disabilityinfofife.co.uk . I have added this site because it has "some" free audio books on it but it also seems to have links to other free media.
http://www.openculture.com/freeaudiobooks
What is Open Culture’s Mission?
Open Culture brings together high-quality cultural & educational media for the worldwide lifelong learning community. Web 2.0 has given us great amounts of intelligent audio and video. It's all free. It's all enriching. But it's also scattered across the web, and not easy to find. Our whole mission is to centralize this content, curate it, and give you access to this high quality content whenever and wherever you want it. Some of our major resource collections include: http://www.openculture.com/faq