While Hong Kong and South Korea are enjoying their iPhone 4S launches today, we here in the U.S. are receiving our own, kind of. As promised, Apple is now offering its unlocked, contract free iPhone 4S at $649 for the 16GB, $749 for the 32GB and $849 for 64GB. The unlocked 4S will only work with certain GSM carriers and Apple even offers help in making that decision:

The unlocked iPhone includes all the features of iPhone but without a contract commitment. You can activate and use it on the supported GSM wireless network of your choice, such as AT&T in the United States.* The unlocked iPhone 4 or iPhone 4S will not work with CDMA-based carriers such as Verizon Wireless or Sprint.

If you don’t want a multiyear service contract or if you prefer to use a local carrier when traveling abroad, the unlocked iPhone is the best choice. It arrives without a micro-SIM card, so you’ll need an active micro-SIM card from any supported GSM carrier worldwide. To start using it, simply insert the micro-SIM card into the slot on your iPhone and turn it on by pressing and holding the On/Off button for a few seconds. Then follow the onscreen instructions to set up your iPhone.

Apple unofficially offered the unlocked iPhone 4S in their retail outlets across the nation shortly after its original launch, but this is the first time they have offered it online.