Grease 13x9 pan. Melt margarine. Add marshmallows; toss to coat with
margarine. Microwave on high 1 1/2 minutes or until smooth when stirred.
Stir in peanut butter. Immediately add cereal. Mix lightly until well
coated. Using greased spatula or wax paper, press mixture into preapred
pan. Cool and cut into squares.