Have an unlocked iPhone. Best pre-paid for Canada?

[Pneumothorax]

Going to spend a week at banff. Looked at ATT's horrible Canada roaming rates. What's the best Canadian GSM Telecom for pre-paid rates? Can I just walk in their store and get a sim card?

 

[stormkroe]

http://www.telusmobility.com/en/AB/prepaid/index.shtml
see what you think of that, you should have covereage over all alberta.