I have searched through all the forums, and I still don't understand. So if anyone is patient enough to explain this to me, I will be greatly appreciative! I have an original iPhone that is serving as an awesome iPod for my kids since I upgraded to a 3GS. I am traveling to Europe soon, and really would love to have an iPhone with me. If I unlock (or jailbreak? I still don't understand what the difference is) my original phone, can I buy SIM cards that would work overseas? And then what phone number does it work under? I'm actually less interested in making phone calls than I am in being able to use all the apps (maps, etc) while I'm there. Would a SIM card help me do that? I would not want to jailbreak or unlock my current iPhone, as I've found that the warranty is incredibly useful. The original iPhone is running 3.1.2 if that helps!