I just got a 3G (4.2.1 & 5.15) and need some advice on unlocking it. I traded my Blackberry for an unlocked 2G 1 1/2 years ago that I am currently using on T-mobile without a data plan. I know I'm not using the phone to it's full potential, but it's great for me! Here are some of my noobie questions about unlocking.

My 2G is synced with iTunes. How do I go about unlocking the 3G and keep my contacts? Will syncing the 3G with iTunes before unlocking it put my contacts on it? Can I sync the 3G with iTunes after it's unlocked without having to unlock it again? The 3G has a different sim card in it now. Should I put my my T-Mobile sim card in the 3G to sync it with iTunes before unlocking? Do I need a sim card in it when jail breaking and unlocking it?

Sorry for all the questions.....just looking for some advice & instructions on how to go about using the 3G on T-Mobile and keeping my contacts.