Hi again, I am going to use t-mobile "pay as you go" for my iphone, but I don't know what is the first thing to do. 1. Which prepaid sim card should I buy? This: http://www.t-mobile.com/shop/Phones...d&device=53299206-c069-429a-82fa-000007a2ac12 or a sim card inside a t-mobile prepaid phone? Which will work? 2. Last of all, If I use the prepaid sim, do I need to change the apn settings and to what?