First of all, what dates are you plugging in? It must be between Aug. 21 and Oct. 4, 2005 to get the dining plan for free. Also, depending on what hotel and view you are choosing the dining plan might not be an option. For instance, I couldn't get it for a woodsview room at the WL but I was able to get it for a courtyard view.
Free does mean free. You get 1 Table Service, 1 Counter Service and 1 Snack per person per day. The Table Service includes 1 appetizer, 1 entree, 1 dessert and 1 non-alcoholic beverage per person on the dining plan. You can order anything on the menu...even the filet mignon! You must pay extra for anything over that. For instance, an alcoholic drink or an extra side or appetizer. Go to this website and it should help you to understand the dining plan better:
http://www.mousesavers.com/mywplusdining.html.