Consider buying a GSM device and even possibly a global SIM card if you want to keep the same number. Global SIMs are available as prepaid and postpaid. There are plenty of threads on this forum although I would suggest a google search. I have a nifty setup with a toll free USA number that forwards to my UK mobile number. I get free, unlimited incoming calls and free incoming SMS. Costs about $0.35 per minute on average outbound...certain areas have higher costs than others.