Samsung Galaxy S III is now a day running through every one’s mind. With already broken the record of pre order sales it is also proving a healthy competitor for other in the cellular market. And the sales itself is a proof of increased consumers’ interest.
So achieving the root on the device was the first priority of the developers on all the three carrier versions, Sprint, T-Mobile and AT&T, of Galaxy S III keeping in mind the increase popularity of the smartphone. And we should thank XDA Senior member howtomen for rooting method of AT&T version and XDA Forum Member cypher_zero for the Sprint and T-Mobile versions.
The rooting method for most Samsung devices is standard. Users will be needed to use the latest version of Odin to flash a kernel and ClockworkMod Recovery onto the device, and then use ClockworkMod Recovery to flash root. The difference is basically the files that are being used in the rooting method for the different carriers. Check out the original thread to root Samsung Galaxy S III from your selected carrier.
Source: XDA Developers