I'm currently using an iPhone 3GS on with iTunes on a Windows computer. I've got a MacBook Pro that I'm using for my new "stuff" (iPad2, etc.). I've already copied my iTunes library from my PC to the Mac, so I can see all of my iPhone apps listed (even though I've never synced my iPhone to the Mac). Before activating the iPhone 4S, it says to create a backup of the "old" iPhone to iTunes first. Should I sync my iPhone 3GS to the Mac before activating the 4S? Or, since the iTunes on the Mac already has all of my Apps, should I just go ahead and activate the 4S and then sync with what's already there? Thanks.