Factory restore the iPhone using iTunes, then insert your sim to see if it will activate it or not, if yes try to get another carrier sim card and insert it in to see if it will also activate or not, if it activate both sim cards then you are having a factory unlocked iPhone, if not then it's a factory locked iPhone.Does anyone have an idea how to know if you have an international edition iPhone 4 ? And any idea of a great site to unlock it I've been burnt quite a lot in the past by scam sites