I agree with PTravel. I've been downloading audio books from my local library for a few years now and have been very pleased with the quality. Overdrive.com lets you transfer directly to an MP3 player, making these audio books eminently portable. No more sitting in the car in the garage waiting for a disc to end! I just unplug the MP3 player and continue listening in the house on headphones.

Occassionally there is a waiting list on the library site for the newest books, but it's not usually that long, and they email me when the book is available to download.