The reservations office had information about what restaurants would and would not be participating by late August, last year, and I believe there was only one change after that. However, the updated list was not yet published (not even on the Disney website) until much later in the year. (Alfredo's wasn't on the list published as late as September 13, and Chefs de France wasn't on the list as late as November 11, 2006.) I'm doing a bit more research, to see if I can pin down the exact date the full list was published.
See below...