My old pal PT hooked me up with a really cool service called SimplyAudiobooks.com that basically does what Netflix does for DVD. You build a queue of audio books you want, they send you the discs, you pop them into your iTunes/iPod/car/etc. and then send them back. At around $20 a month if you listen to one and a half books a month you’re easily in the black.
If you do signup feel free to say jason at calacanis dot com referred you (I’ll get a free month I think, plus I want to see if I can get them to advertise across our network since they are so rad.