By Jim Karpen
Unlike most other places in the world, in the U.S. you're typically tied to a 2-year contract when you buy an iPhone. That's because the phone actually costs much more than what you're paying for it, and the carrier recoups the hundreds of dollars it pays to susidize each phone by obligating you to sign a contract.
In other countries, it's much more typical for users to buy phones outright and then simply purchase SIM cards from whatever carriert they want. SIM cards are sold on the streets in vending machines. You buy the SIM card almost like you'd buy a calling card. You simply plop the SIM card in your phone, and you're in business.