LibriVox: Free audiobooks

LibriVox promotes the "acoustical liberation of books in the public domain":

LibriVox volunteers record chapters of books in the public domain and release the audio files back onto the net. Our goal is to make all public domain books available as free audio books.

They recently celebrated the release of their 1,000th audio book. Recent releases include Karl Marx's "Wage-Labour and Capital" and Edgar Allan Poe's "Murders in the Rue Morgue."