is your phone the only place you have your contacts? on a mac, the program that can sync your contacts is called address book. a lot of other people use outlook too. I also have my contacts synced to the cloud on mobile me. there are also many other third party contact applications out there.
when you set it up as a new device you'll have to tell itunes to sync your contact info along with music and photos and calenders. make sure you have everything you want synced checkmarked.
07-20-2010 12:56 AM