Ok I already have an iPhone which has been activated via AT&T, and I have an active service with them. What I now want to do is, unlock/jailbreak this phone, and transfer my active iPhone plan to a new iPhone which I shall be buying. So basically, how do I go about this? Can I simply just switch SIM cards? Will the new iPhone detect an already active SIM and be activated, or will I have to do some hacking for this? I'm sure there is a native method for this, since quite a few people have replaced their iPhones, hence you can definitely transfer this over. But how exactly is this done?