This is not quick and easy, but....
My boss got a new computer and had all his Music on his iPod, but not on the new system. He also didn't want to re-rip all his CDs. So, we did not steal this music. He wanted all the music from his iPod on his new system.
First turn on the Firewire hard drive feature (in iTunes for the iPod). To do this, plug in the iPod, go into iTunes, dbl click on the iPod (in the source mox) so it opens in it's own window then click the iPod button on the lower right (not the eject button), then sellect enable firewire disk use.
Now mount the ipod on the desktop (if it isn't already) and right click it. Then select duplicate. It will make a copy of the iPod.
Then use FileBuddy (go to version tracker and download it. Great program. Buy it. I did. Keep this buy making it better!). Open up filebuddy and do a get info on the invisable files where the music is. Specificaly iPod_control/Music/"every folder inside". Make these files visable by unchecking the invisable box.
drag all your MP3s to another folder. Trash the remaining junk.
Viola