A friend of mine who owns a Verizon iPhone is traveling to Italy soon. He went to a local Verizon store and had his iPhone 4S unlocked. And, he intends to use a GSM SIM in it once he arrives in Italy. He has no overseas talk or data plan of any kind with Verizon. In this configuration, while he is in Italy, I have the following questions: Question 1. What would happen if someone in the US dials his US phone number? Will his iPhone recognize the call as a roam call? Or, since it is a CDMA call, will his iPhone remain silent? Question 2. Hypothetically, if he had a Verizon overseas calling plan of sort, would his iPhone effectively become a dual-SIM iPhone? Since I have never owned a CDMA iPhone, I don't know the answers to these questions. Would you mind chiming in for me?