Hi everyone, While I was in the States last summer I bought a GoPhone; I opened it and my iPhone 3G up and they have identically-shaped SIM cards. I bought the iPhone 3G on release day here in Japan but I don't want to use roaming on it when I'm in the US next week (I land August 26th). My question is: Can I swap a Motorola cell phone's GoPhone SIM card with an iPhone 3G's SoftBank SIM card and use the iPhone 3G in the States? If so, can I also use cellular data and how much does data cost? Thanks for your time!