I remember that when I was in the States, you can 'rent' books on tapes from Crackle Barrel. You then sold the books back to the stores when you are done. They are a pretty neat idea.
Now, with the advent of iTunes and Podcasts, you can have a ton of free audiobooks downloaded in pretty much every genre. http://www.apple.com/itunes/podcasts/
Personally, I like the ones that have more of a dramatic flair to them, my favorite for the last little while was the seeing ear theater series, which can be found at http://www.scifi.com/set/