Copy purchased music from one authorized computer to another using an iPod

iTunes 7 has a new feature that will transfer purchased music from an iPod to the iTunes library of any computer authorized to play its music (you can authorize up to five computers to play music purchased with a given account):

1. Sync your iPod with the computer that pruchased the music.
2. Connect that iPod to another authorized computer, and you are given two options:
a. "Erase and sync" the iPod with 2nd computer, severing the link to the 1st computer.
b. Execute a one way "Transfer purchased music" from the iPod to the 2nd, authorized computer's iTunes Library.

These two items also available in the File menu.