the Disney Dining Experience (DDE) is a program available only to annual passholders. the way it works is that you purchase a DDE card (similar to a credit card) either over the phone or on-line for about $60. then you can use the card for a 20% discount on table service meals at most places on WDW property for yourself, your family.....up to 10 people in your party, i believe (someone pls correct me if i'm mistaken on that).
DW and i used our DDE card for the first time this past JUN and it worked out very well. even though 20% really only negates your tip, it adds up over the course of the week - or in our case this summer, two weeks!