Microsoft and Harmonix confirmed today that all of Dance Central's routines will export to Dance Central 2 for 400 Microsoft Points ($5).
It should be noted that if you were not a fan of the "freestyle" sections in the original Dance Central, they are still part of the exported songs, even if you turn off the freestyle section in Dance Central 2. There was no choreography to cover those sections in the first game.
Participating retailers are offering 400 MSP with pre-orders of Dance Central 2, subsidizing the transfer charge. Dance Central 2 hits the streets on October 21 in Europe and Asia, and on October 25 in North America.