iTunes allows you to copy MP3s from your computer to your iPod, and do everything but copy those MP3s back to your computer. But now with iPod Viewer, you can do just that! Just launch the application, import the songs from your iPod, select the songs you want to copy, choose where you want to copy the songs to, and transfer the files. That's it!

Caution: iPod Viewer 3.0.0 requires Jaguar (MacOS X v10.2) or greater!
 download iPod Viewer 1.5.2, which runs on Mac OS X v10.1

iPod Viewer is a freeware application. No charge, just download and enjoy!