Sources within United States Apple Stores have told 9to5Mac that shipments of four new iPhone models have reached their respective Apple Store locations today. As originally reported by ChronicWire, the model numbers are in fact MC603 (16GB, Black) MC604 (16GB, White) MC605 (32GB, Black) MC606 (32GB, White).
Those model numbers match up with unlocked iPhone 4s sold internationally. Retail sources say the delivery of these new phones was unexpected and the current plan is for availability starting Wednesday. Separately, MacRumors reports that the unlocked iPhone 4s will cost $649 and $749 for 16GB and 32GBs, respectively.