I may be getting an iPhone soon, so I need to know basic information about it. More specifically, I want to know how the iPhone works in terms of the carrier and the SIMS card for the phone. If I were to buy an iPhone at other stores (e.g. Best Buy, Fry's, and other electronic shops) or online (Amazon, etc), would I be able to insert my own SIM card into the iPhone for it to work? Or must it involve a jailbreaking/unlocking process of some sort in order to "unlock" the iPhone? Basically, what I want to know is the "phone" part of the iPhone, as I'm perfectly fine with the other functions. I did search for information about the iPhone, but I only looked at the basic parts of it, such as setting it up in general. Any other information about the iPhone would also be helpful Thanks.