I'm probably going to buy the Treo 600 today, as an upgrade from my old treo. Then the phone will be $400. Once I get the phone, I plan to activate the phone w/ Sprint (probably on 11/24, to keep my phone #). Will Sprint give me a service credit when I sign up for a new plan? Should I sign up w/ Sprint through Handspring, or just get the phone for now and sign up later?