i have an iphone 4s sprint model and a verizon model. i recently ran across a website called iphoneoperatorcheck.com. It gives info on iphone and shows 'unlock status'. i ran both imei's of 4s that i have and it shows them to be unlocked. what does this mean? are they only unlocked internationally or could i put a sim from US carrier into either one of them. any help is appreciated. thanks