Double Delicious Halloween Bars

1/2 Cup margarine or butter
1 1/2 Cups graham cracker crumbs
1 14 Oz. Can sweetened condensed milk
1 12 Oz. Package milk chocolate chips
1 Cup peanut butter chips

Preheat oven to 350 degrees (325 degrees for glass dish). In 13 x 9 inch baking pan, melt margarine in oven. Sprinkle crumbs evenly over margarine; pour sweetened condensed milk evenly over crumbs. Top with chips; press down firmly. Bake 25 to 30 minutes or until lightly browned. Cool. Cut into bars.