plan using the same phone? I would like to get out of the monthly contract game since I don't use the phone all that much but I still want to keep the same phone that I have. Does this require a phone number switch? Easy 10 points.

No. All you need to do is pay and early termination fee, then get your SIM card into a "prepaid" one, costing $10. When you get it activated (by calling Tmobile) tell them that you want to keep your phone number (which they'll let you). Or when you get the phone terminated (the contract) tell them.