well, apple had to cripple (or at least make it not too obvious) the ability to move songs from iPod to computers for a reason: piracy. what's to prevent anyone and everyone from having an iPod party and downloading everyone else's music onto their laptop?
iPod, however, is a FW HD at the core, so there are ways around this, of course...
basically:
if the music can be played on the iPod (i.e. loaded to iPod via iTunes), then you need a 3rd party app to move them back to the computer. if the music is simply stored on the iPod in the FW disk mode, then it's just drag and drop back to the computer. no dependence on the format of the music.