There's a list here:
http://www.gwu.edu/~action/2008/primdeb08/primdeb08main.htmlHowever, I don't know if all of those are really going to happen. Those are the debates that have been proposed by debate sponsors, but they'll only happen if the candidates agree to them. Are we really going to have debates for the two parties on the same day in Dec. 4th, or GOP debates on back-to-back days on Dec. 3rd-4th?
What I'd really like to see is a comprehensive list of which candidates have agreed to each of the debates, but I don't know where to find such a list.