I have wifi at home, so to conserve battery I only use edge when at home. I'm noticing that on my iPhone 4, when I make or receive calls on EDGE, I hear an intermittent popping or clicking type of noise. At first I thought the person I was talking to kept touching the microphone on their phone. Sometimes I can hear it on 3G, but not as loud as when on EDGE. I've called my other phone and placed my iPhone 4 on Hold, and I was STILL able to hear the noise. Can someone please make a call on Edge to another phone and stay on the line for a few minutes to see if the same happens for them? It gets really annoying after a while. I can hear it when using the handset earpiece and also the earphones(which is REALLY annoying because it's more audible).