In large saucepan melt margarine over low heat. Add marshmallows and stir until completely melted. Remove from heat.
Add the cereal and crushed oreos. Stir until well coated.
Using buttered spatula or wax paper evenly press mixture into 13 x 9 x 2-inch pan coated with cooking spray. Melt chocolate chips and cover the top of the bars. While the chocolate is still warm sprinkle the finely chopped oreos over the top.
Cool. Cut into 2-inch squares. Inhale.