I currently am a secondary line on an AT&T familiy plan. If I switch to using an iPhone, I understand that I will have to pay the additional $20 for the data plan, but I am unsure about the other fees. I currently have to pay $9.99 a month for my line (a secondary line on my current family plan), but will I now have to pay $29.99 for the line, because it is an iPhone? Or does the $29.99 fee only apply to family plans with more than one iPhone(or just the iPhone family plans listed)? Does anyone have any experience with this plan upgrade/know how much it is going to cost me per month? Thanks!