billing address at initial setup? OK, here's the question. I purchased an iPhone recently, but have not activated it as of yet via iTunes.Next January, I will be attending graduate courses at a school in another area code (I will be commuting), and in preparation for class projects, discussions, etc., I would like to be able to activate my iPhone with a new phone number in the school's area code, rather than my own billing area code. There is also a distinct chance that within the next two years, I will be relocating to this same area code as my primary residence.My question is: (1) Is this even possible? (2) If so, can I do this using the iTunes interface, or would I have to go through an AT&T representative?Thanks in advance!