Our two favourite sources for completely free audio books are BooksShouldBeFree.com and Project Gutenberg’s Audio Books Project.

http://www.booksshouldbefree.com/

http://www.gutenberg.org/wiki/Gutenberg:The_Audio_Books_Project

BooksShouldBeFree.com’s free audio books for downloading are all read by volunteers, and some of them are very good.

Project Gutenberg’s free audio books project offers two different types of audio books for downloading: those read by human volunteers, and those ‘read’ by a text-to-speech computer program.