Overdrive.com has a beta app for audio books. Just got it today. So far, so good. I use it for libray downloads. Uses mp3 format. Don't know if it can be used for all mp3 audio books or nto, but I know people have been loooking for audio book apps, so I thought i'd pass it on. The beta is free. The PC version is free, so I don't think they'd charge when the real version comes out.