answer:if you are on 1.1.4 upgrading to 2.0 all of your music will be removed. When it says “backing up” it is just backing up your settings, contacts, bookmarks and webclips. You will have to put all the music from your computer back on. Depending how much music you have, that can take minutes to hours. On aside note, the upgrade to 2.0 is well worth it. There are a few slowdowns, but there are many apps in the appstore and you can still jailbreak it for more apps.