You can go to www.allearsnet.com and click on dining. There are lists of menus that give you an idea of what the theme is. If you don't have reservations for this Christmas, you may be out of luck for the most popular restaurants. People can make reservations 6 months in advance for Christmas Day.
If you are going in 2007, don't be afraid to check out the restaurants in the hotels, too. There are some nice once in the contemporary, Poly, Yacht/Beach, Animal Kingdom Lodge and Wilderness Lodge.
We went to Liberty Tree Tavern. It was a nice family style meal with Ham and Turkey as well as Roast Beef. We had almost the same menu we would have had at home without having to clean up later.