I love audio books. I’ve found them to be a great way to stay awake during long drives, because it literally sounds like someone is talking to you the entire time. Music, especially music you’ve heard dozens of times, is easy to tone out but audio books aren’t.
iTunes and iPods/iPhones have the ability to remember where in the book you stopped should you pause or disconnect your iPod. This is tremendously useful because I drive different cars and scrolling through a 54 hour long audio book to find my spot is a pain. The catch is this functionality only works on audio books that are in a particular format that only Apple or Audible.com support.
Well I get my music from a variety of sources, much of it in MP3 format from rented audio books. iPods don’t remember where you stopped on an MP3 file, only on the M4B format. I did some Googling and as recommended by Michael Alderete I downloaded and used MP3 to iPod Audio Book Converter. It converts MP3 audiobooks to the M4B format, can combine multiple MP3 files into a single file, and is free. Best of all, it works wonderfully.