I'm not a very smart person when it comes to cell phones. They confuse me. I can do my research, but so much of what I need to know doesn't seem to be easy to find out online, and the potential to lose hundreds of dollars buying a useless phone is pretty risky.

Let's say person A (we'll call him 'Tom') really wants a particular phone (let's call it an 'iPhone') and a particular carrier (let's call it 'AT&T'), but AT&T doesn't offer iPhones for sale.

• Can Tom jailbreak jailbreak his iPhone and use it on AT&T? Is there any other way to use his iPhone on AT&T that wouldn't violate the warranty?
• How could Tom get a phone number for an iPhone he bought without a service plan?
• Would Tom get into trouble if he explained to AT&T that he wanted cell phone service for an iPhone?
  
• If Tom lived in another country, could he buy an American iPhone and use it in his country (let's call it 'Canada') without problems?
• Is Tom basically an idiot for not using a phone provided by his service provider, or switching providers to one that supports his phone?

Note: 3 out of 4 of the following terms were made-up: Tom, iPhone, AT&T and Canada. Thanks for your patience!