Hi, I currently have an Iphone 3g and am thinking about renewing my existing at&t plan to get the iphone4, but that one I'm going to be giving to someone else. so would i be able to take the sim card at&t/apple would provide me for the iphone4 and use that in my 3g? as the iphone4 i'm going to give to someone overseas so they don't need the sim card that comes with it. Also does anyone know if the latest OS version has be unlocked? Thanks.