On my previous Dell notebook, my ipod nano worked just fine with itunes, no issues at all.

Now that I bought a powerbook, when I plug the ipod into it, the nano recognizes it's not the original computer and asks me if I want to erase everything and associate the ipod with the mac. I don't want to do this as I have tons of music on there (some of which I didn't originally back up on my Dell).

Is there software to back up my ipod so I can transfer all the music over to it, erase the nano and then put it all back on here?

I'm sure this question has been asked 10,000 times before but I just want to know the easiest way to do this.

TIA,
Dale

I use iPodRip, it will get all of the music, photos and videos (if a 5g ipod) and put them in a folder on your Mac. The trial should work for what you want to do.
http://www.thelittleappfactory.com/application.php?app=iPodRip:)

You could also just download an app like Tinkertool or Onyx and turn on "show hiden files and folders", access the iPod through Finder and drag off the files.