If you check out an Overdrive mp3 audiobook from the library, and your Overdrive software refuses to recognize your mp3 player, this doesn’t mean you can’t transfer the files. It just means you have to transfer them without the aid of the software, and without all the additional non-mp3 files.
Naturally, you are still bound by honor to delete the files at the end of your loan period. But it’s a lot better than having to haul your computer around.
I have been using Overdrive recently because Audiobooksync.com was releasing two free novels a week to download and use via Overdrive. 18 books released over the summer and most of them quite good.
Once I got the MP3 files I converted them to audiobook format to play back on my iPad.
They still have two weeks left for releasing books.
http://www.sffaudio.com/?p=21521