Here's a feature that's looooong overdue. Now if they could just get two computers using the same drive for iTunes (say a Mini running OS X and Windows) without screwing things up. From engadget:

10:14AM 'Home sharing: we're going to let you copy songs, TV shows, etc. with up to 5 computers in your house. You're going to see all the computers you can share with, and you'll see the contents -- you'll be able to drag that and copy it to your library.'