I just heard of LibriVox last night. What an awesome use of technology.
LibriVox volunteers record chapters of books in the public domain and release the audio files back onto the net. They are a totally volunteer, open source, free content, public domain project. Their objective is to make all books in the public domain available, for free, in audio format on the internet. LibriVox, volunteers record chapters of books in the public domain into digital audio (eg. mp3), and then make the audio files available to the world, for free.