Rental

Audio Diversions - Store with audio books on cassette, cd, and mp3 to buy or rent.
AudioMysteries.com - Rent mystery audiobooks on CD and MP3.
Audiotogo - Audiobook rentals on CD or tape.
Books in Motion - Formats offered include cassette, cd and mp3. Includes links to author sites as well as tips for first time users.
Booksfree.com, Inc. - Uses a monthly membership model to rent paperback books as well as audio available in both CD and MP3-CD format.
ComeHearBooks - Abridged and unabridged audiobooks rental and sales.
JiggerBug - Audiobook rentals available on CD, cassette or by download.
Kitabe.com - MP3 Audio Book rentals to members in the US and Canada.
Simply Audiobooks Inc. - Content available on CD to the United States and Canada. Uses a monthly membership model.
The Talking Book Club - Has both a rental and buying model for audio books in both CD and tape formats.