Hello all! Just got a new iPhone 4 and I have a few questions. I only subscribed to the 200 mb data plan because I have Wifi at home, school and work so I wouldn't be using it other than that really a whole lot! I think the 200 mb would be plenty for the use that I will be doing out of a Wifi zone! Anyway, I've been using the iphone at home and I used it for maybe 5 minutes total yesterday without Wifi. I checked my data usage today and it says I've already used 16.0 gb in ONE day even though I've hardly used it at all. I called AT&T and they said something about the app not turning off by itself. But I'm not understanding because I've only been in a Wifi area. I tried looking up info and I don't understand much of it. Anyway, I just went to my Settings and turned OFF Cellular Data. I can still use my Wifi and place calls. Is this the right thing to do? Does this mean I will have to turn ON cellular data when I want to use it out of a Wifi area?