http://www.mousesavers.com/mywplusdining.html
Check this site for info. You can download the brochure, which has a list of participating restaurants. The site also lists a couple of places that have recently been added, but are not in the brochure yet.
When I checked last, Cap'n Jacks (sit-down) was the only place on the plan. I think someone reported being able to use it at a CS place, but they were given a spending limit. Not sure if that hiccup has been cleared up yet......