Apple might not be officially selling unlocked iPhone 4S handsets until November, but in the United States, it would appear that “off contract” AT&T iPhone 4S smart phones are indeed unlocked handsets, and can be used with other carriers.

The news comes in an article recently published by 9to5Mac, and has also been discussed in MacRumors‘ forums. Apparently, customers who purchased an “off contract” iPhone have been seeing the below message in iTunes, which reads: “Congratulations, your iPhone has been unlocked.”

Congratulations, you're now rocking an unlocked iPhone 4S

John Gruber has also noted (via Twitter) that Sprint iPhone 4S handsets also appear to be GSM unlocked. He wrote:

If you pop a Canadian SIM into a Sprint iPhone 4S, it just works. Not locked.

However, Sprint recently noted that it will be locking iPhone 4S handsets in the near future via a software update.

The prices for AT&T’s “off contract” iPhone 4S handsets areĀ $649, $749 and $849, for the 16 gigabyte, 32 gigabyte and 64 gigabyte models.

Have you been able to confirm that AT&T’s “off contract” handsets are unlocked? Let us know in the comments.