You get $100 off the price of a regular AP and $125 off the price of a Premium AP. This is for the adult passes. I'm not sure if the discount is different for passes for kids ages 3-9.
The dining card is the Disney Dining Experience card. You can only get it if you are a Florida resident or an AP holder. It costs $60 (plus $25 if you'd like a second card) and it gives you 20% off of food/beverages (including alcohol) at most sit-down restaurants and some counter-service places at WDW. Here's more info on the program...
http://allears.net/din/dde.htm