Originally Posted by Moi un Mouton
From what I have read, your phone will be locked to Rogers. You can solve this by jailbreaking and unlocking the phone, which is easy enough.
You do not have to jailbreak your device to unlock it. Search the forum for unlock without jailbreaking instructions. That should help.
Also, nearly every carrier outside of the United States of America that offers the iPhone as a device under contract is either owned by AT&T (like Bell or Bell South) or has a contract with Apple like AT&T has which can exclude many carriers using GSM/GPRS/UMTS technologies. However, an unlocked iPhone is compatible with only GSM/GPRS/UMTS technology so goto: http://en.wikipedia.org/wiki/Mobile_Network_Code
to find your carrier and make sure that the network is compatible.