Dissolve gelatin in 1 c warm water. Set aside to cool. Mix together 6 pkgsweet/low and graham cracker crumbs. Add melted margarine. Press 2 c ofcrumb mixture firml;y into 9 x 13 pan. Reserve rest for top. Cream 16 pkgsweet/low with cream cheese. Stir in prepared whipped topping. Pour mixtureover crust and sprinkle with remaining cracker crumbs. Chill 3-4 hr. Alsofreezes well. ( 37 calories per square), Makes 36 squares.