If you are buying it from a dealer, they can give you a temp transport sticker that is only good for 10 days! Try going to the sec of state and getting one of those!
Yes, that's a good idea. Also, in most states, the Department of Motor Vehicles (what we here in Illinois refer to as the Secretary of State's office, as Steve notes) has a pretty good website where you may find answers to questions like this. Also they usually list their office locations where you can go to get the temporary registration or whatever it's called.