Thanks for the links. According to MACWORLD it can be done, and quite easily.
The USB iPods won’t charge from the keyboard USB port. You need to plug it directly into the computer via an extension cable.
Officially, getting music off an iPod to another computer cannot be done. This is primarily done as an anti-casual-piracy maneuver.
Unofficially, it’s as trivial as finding the hidden directory on the iPod where the files are stored, and copying them over. Anyone who feels comfortable navigating the iPod’s directory tree can do it inside of three minutes.
If you were asking “can i sync my current iTuines with the newly purchased iPod and pull songs off of my iTunes onto this iPod” it can be done, but I think what you will need to do (short of wiping it and restarting) is have the original owner log on to your itunes (using Advanced/Authorize computer) and provide permission for you to access the files via iTunes.
I don’t there’s anyway to merge an existing iPod loaded with songs to your iTunes login short of wiping it.