Also if you don't know, last week Rock Band pushed an update that allows you to export your Rock Band 1 songs onto your hard drive so that you can play them in Rock Band 2. It costs $5, but that's a steal and you no longer need the disc, so just trade it in.
This is such a good idea. I've wanted Rock Band/Guitar Hero to do something like this so I can have a sort of mix tape of my favorite songs and get rid of the shitty ones. Way to go team!