Probably too late. The only thing you have to pay is the $30 (+tax) for getting an iPhone. All other minutes, unlimited text, etc transfers over directly from your old phone to the new one.

I know you'd need to pay the data charge, but the minutes and texts should comply with what your current plan states it does. So probably not anything besides data. Sorry I can't help more, but I don't have ATT.

I already have an at&t account and want an iphone. My family has a plan with like 5 phones on it and we have unlimited messasging and a set talk time and everything. If i would buy an iphone, all i would have to pay exrta is the extra $30 media package a month right?.....would there be any other costs since i already have a plan?