3g usage will increase even those u off the edge/3g but it only increase very very little....

i'm on unlimited plan cause 3gb not even enough cause i'm heave user.... in a week i can used up to 4gb that stated in iphone but as we not iphone usage r not accurate....

so for those who din use unlimited plan pls bear in mind always off ur 3g or edge, non-jailbreak iphone user have to becareful...