Considering to buy an iPhone?

I am considering an iPhone and I have a few questions. I am an AT&T Existing Customer so can AT&T just do a phone to phone transfer and transfer my contacts, pitures, etc to the new phone. Also, since I am on a family plan can I keep my Unlimited texting that I already have. Or would it not work the iPhone. Lastly, could I keep my existing Talk plan since I am the only iPhone on my Family Plan?