It doesn’t provide the level of detail, screenshots, etc. that I would like, and it’s not focused enough on audiobooks, but Lifehacker has an article that outlines a procedure you can use to convert audiobooks on cassette tapes into MP3 tracks you can listen to on your iPod:
Lifehacker: How to Digitize Cassette Tapes
It’s basically as simple as using a specific cable to attach the line out on an ordinary tape player to the line in port on your computer or sound card, and pressing the record button in Audacity.
I think the article needs more screenshots, and details of moving the tracks into iTunes, and I think their recommended recording format (128 bit MP3) is not optimal for audiobooks, but if you’re trapped for days and need a break this holiday, the instructions will certainly get you something usable.
We have a great service for digitizing cassette tapes and have transfered 1000’s of audio books to date. There is an article about the ins and outs of digitizing at home versus using a service at Reclaim Media’s article page.