I have GSM cell phone with AT&T service. I would like to unlock it and use on some other network such as Metro PCS. I was wondering if it is possible to use unlocked GSM phone with a SIM card on some CDMA network. I would like to use it on Metro PCS. Can an unlocked GSM cell phone with a SIM card be used on a CDMA service, preferably Metro PCS? How can I do it? I would really appreciate your useful information regarding this. Thanks.