There's only the main Disney site:
http://disneyworld.disney.go.com/restaurants/
Select the restaurant you want and click the Book a Reservation link.
Once the booking engine loads, look for the following:
Do you have a Resort reservation for the same days for which you're making dining reservations?
If so, please retrieve your reservation.
Click on the words 'retrieve your reservation' and enter your
DVC confirmation number and phone number.