Cell phone advice needed

I don't know too much about cell phones, so I would appreciate some advice.
I would like to get a prepaid plan (with a phone) from Petro Can, PC or 7-eleven. If I take the sim card from one of these phones, can it be used with a Rogers phone (the contract is over)?

Why did you post this in "Hot Deals"? Did you really think it belonged here?

yup 7-11 speakout and petro sells unlocked gsm phones, you dont even need to activate them, just pop in your fido or rogers sim and away u go