Wes Fryer just wrote a great post on Copyright and Licensing Considerations When Importing Audio Books. It's a perfect extension on the information in my post of June 23rd regarding fair use and copyright.
In the scenario from my June 23rd post, the main concern was the fact that the audio recordings of the books would be posted to the web. When you get right down to it, recording a book or ripping a recording of one, even for personal use, breaks copyright law even if it's never reposted anywhere or shared with anyone else. I decided not to go into that when I wrote my post, but Wes does a great job of going into those details in his blog post. He even touches on recording content from out-of-date technologies such as VHS or cassete tapes to digital formats for continued use. I encourage you to read it and share your thoughts!