I'm in a supported 3G area, but I can't get my phone to connect to 3G, just Edge and Wireless. It's a new phone I got today, does 3G need activation, or is there something else I need to do? I have enabled 3G on the device, when I turn this on, I immedietly get 5 bars of 3G signal, but then it slowly drains over about 20secs back to Edge. it's a new sim, just the one they gave me in the shop yesterday but it says iPhone 3G on it. Thanks.