Yes, you can. You can either cancel your current contract and pay $175 for that, then buy the phone for $199 and get a new contract... Or if you have a nice voice plan that you dont want to loose, you simple pay the full price for the phone. ($399)
Canceling the contract will save you $25 up front, but you will end up paying for for your voice plan.
I have an old 750 minute family plan for $49, so I will do everything to keep that as long as I can. (Never gone over, and we have 6k rollover minutes.)