I recently rented The Lord of the Rings in audiobook format, on CD, from Recorded Books. They make, sell, and rent audiobooks. When you rent, they send you the books in a box-within-a-box. The inner box is for sending it back, so there is very little hassle.
Don’t tell them, but I am ripping the whole set into MP3 format, so that I can listen on my iPod. I am not doing it to steal the books, or put them up on Limewire, I just want to put the data in my own bucket, as it were. It’s very relaxing to kick back and listen to a book, so I recommend poring over the selection at Recorded Books.