When you pre-order Dance Central 2 at Amazon now, you not only get $10 credit, you also get 400 Microsoft points, which can be applied towards transferring original Dance Central songs to Dance Central 2. It applies retroactively to all previous pre-orders as well. Unclear whether this is an Amazon Only deal or will be applied to preorders at other vendors.
UPDATE: Looks like this deal is available for people who preordered from GameStop, Amazon, Best Buy, and the Microsoft Store. So that’s good news for everyone except folks like me who preordered from NewEgg.