Although there are many solutions for getting the hidden audio files from your iPod back onto your Mac, many folks have long considered PodWorks to the best of the lot. After more than two years since the last update, it was revised this week to version 2.9. The most significant improvement is that it's now a Universal Binary, though there have apparently been some bug fixes with regards to videos and an update to the interface. If you only need to transfer songs occasionally, the donationware Senuti will probably be adequate but if you're regularly transferring songs, I suggest giving PodWorks a look.
PodWorks is $8 and a demo is available.
[via Infinite Loop]