I have T-Mobile and I want to get an HTC G1 Unlocked phone so that I can use it with T-Mobile but I don't want to pay for the data service, the G1 has Wi-Fi so I will use that where available. My question is can I put my SIM card into the HTC G1 unlocked phone and use the voice service? The reason I ask is T-Mobile requires the data plan with this phone, but I assume it does not matter if you use one that is unlocked, is this correct?