The iPhone 3GS is only available on AT&T, but newer models are available on more carriers.
Right now you can get the iPhone through AT&T and T-Mobile. All you do is order a sim card and you can use T-Mobile on your iPhone. WHen it will be able through other carriers some people say will be in January when the iPhone goes to Verizon, and October when it goes to Sprint.
no, they are the exact same phone just with different carriers.
The iPhone will always be available on AT&T, but since 2010 they expanded to other carriers such as Verizon (2010), Sprint (2011), and T-Mobile (2013).
In America, the two SIM-using GSM carriers are AT&T and T-Mobile. T-Mobile can only use it's EDGE network on an iPhone with a SIM Card needed.
It is from AT&T. It's been on its contract with AT&T for a while, but it is hopefully going to be up soon with Verizon Wireless and possibly other carriers.
No, iPhone imei can't change, it's unique. T
One of the lrgest and best US cell phone carriers is AT&T,they have the Iphone. You can also get great service and phones thru Verizon.
You don't need to be jailbroken now that the iPhone supports most carriers. The iPhone 4 is physically unable to switch from GSM to CDMA carriers anway.
Contact AT&T if you want to change the name on the contract. Or if you "found" it restore it and change the SIM or take it to AT&T
The iPhone is only available for AT&T and yes, there is an iPhone-specific data plan that is required. iPhone's that have been "unlocked" can be used with other carriers such as T-Mobile or Verizon, but even then an extremely large to unlimited data plan would be required (otherwise, you would have a LOT of overage charges since the iPhone is connected to the internet at all times).
I don't believe any carriers still sell the iPhone 3GS or older, especially considering they offer the iPhone 4 now for free (with contract).