I have recently replaced my PC with a MBP. When I sync my iphone with the new mac for music, it said my iphone is synced with another itunes library and I have to erase the iphone content in order to sync with the new library. If I select erase and sync, does it erase everything, or just the music portion? I want to keep all my apps but just sync music, is there a way to do this? Also, my iphone has all my contacts and my mac has none. So, if I check the sync box for contacts, does my contacts transfer from my iphone to the mac, or do they transfer from the mac to the iphone (which means it erase all my contacts in the iphone)? Obviously, I want to transfer my contacts in my iphone to the mac, how should I do that? Thank you!