Changing phones, not plans--how??

I'm thinking about getting an unlocked samsung d807 to replace my razr v3. The razr is at&t and the samsung is just unlocked, though at&t sells it. Can I just take the SIM out of my razr and put it in the new phone, and it will work? I don't want to buy the phone, get it, and just have spent $200 on an expensive paperweight. Any help appreciated.

just take the sim out of the razr and put it in the unlocked samsung. you shouldnt have any problem.s

cool thanks