Because I can´t backup my iPhone 3G without deleting first the backup folder (library/Application Support/Mobile Sync/Backup). And then when I do that the backup takes about 4 FREAKING HOURS!!! Without deleting the backup folder first, it always gets stuck and never finishes. I´m now trying to switch from the 3G to 3GS and I need to backup first all the data and I was nearly done (at over 3 hours) and then my mom calls! And after the call the backup got stuck!!! AAAAAAAAAAAAAARGH!!! I have to start again from the beginning! THIS IS DRIVING ME INSANE!!!