Hi, I'm heading overseas in a week or two and want to unlock my iphone so that I can use some cheap prepaid sim cards and not run up a massive bill. However, I read somewhere that if you unlock your iphone and associate it with your original iTunes account, you wont be able to use it as a phone, just a Wi-fi and media device? Does anyone know if this is true? Thanks, Liz P.S. I plan to restore it to its unlocked condition when I return - does anyone know of any problems associated with this?