There is also an Orlando "Kids Eat Free" card that you can purchase but it gets mixed reviews on its value. http://www.kidseatfreecard.com/
You also need to pay attention to beverage prices. It's not unusual for beverages to be an extra that are not included in the "free" part of the promotion.
And don't forget to look at the total picture. "Kids Eat Free" might sound wonderful until you look at the cost of the adult entrees (which you must purchase to get the free kids' meals).