Combining iTunes Libraries?

as far as duplicates go, your itunes will pick them out for you. with the itunes open, go to "edit" and click on "show duplicate songs". it should be near the bottom of the "edit" window.

 

There is a setting which looks for all music on the computer and puts it all in one place. I'm presuming you've got Mac's, so if you go into firewire drive mode on the old computer, plug it into the new you should be able to use this function to combine the two.

Shame I can't remember what its called! Anyone remember? I'll check when I get home if I don't remember in the next 30 min...

EDIT: Consolidate Library!! That's it. Its in the Advanced tab in preferences. Should work. And it takes playlists and playcounts with it.