You have to have an Annual Pass to participate. If you have one sign on to the Passholder portion of the WDW site and check special offers. The BR also usually comes up in an ad/picture/spotlight at the top of the first sign on screen. You can book your room, but has to be within at least 60 days advance. And I think dates thru Feb 06 are available right now. There is a 1 night non refundable deposit required.
HTH