Finally Apple started selling Unlocked iPhone 4 (GSM) in the U.S. for the first time, while the company had been already selling unlocked version of the device on other countries. The great thing of buying an unlocked iPhone is for international travel, as the device is not dependent on any particular carrier. In the U.S. unlocked GSM iPhone works perfectly for AT&T network however, on T-Mo there’s incompatibility using 3G network but works fine for voice calls.
If you don’t want a multiyear service contract or if you prefer to use a local carrier when traveling abroad, the unlocked iPhone 4 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.
Don’t be surprise if the price listing booms to 4x the normal carrier-locked devices, unlocked iPhone 4 starts at $649 for a 16GB model and $749 for 32GB model. Both White and Black models are offered.