Hello,
In order to book a room through the Passholder Best Rate Program, you must have your Annual Pass or exchange certificate. Go to the Passholder page on the Disney website and enter in your passholder number. Next, click on the "Special Offers" link. You will then see the Passholder Best Rate Program, click on that. Once there, you click on "Book Now" and it will take you to the reservations page. For this program, you must book 120 days in advance, and right now they are allowing bookings with arrivals by 12/19/05. Once you pick a date and resort, if your choices are available, you will see a white box at the top of the page telling you it is the Best Rate Program. HTH.
Andrea