I currently have a fido phone but i want to upgrade my phone. I dont like fido's phone but i dont want to change providers as fido has the best prepaid plan with per second billing. So i want to buy a rogers phone but continue to use fido's servive. Can i do that?

I can't see why not. The technologies are the same and they use the same network. Just to be sure, though, I would contact your local Fido dealer and confirm with them. I took a look through both of their websites and they just indicated that they were integrating their GSM/CDMA networks to increase network coverage.

yes u cann, if problems arise with sim. ask for a sim unlock from fido.