Combine peanut butter, icing sugar, butter (or margarine) in a bowl, set a side. Put Rice Krispies into a plastic bag. Roll with a rolling pin to crush well. Add to bowl and mix well (you may have to use your hands. Press into a greased pan, use a water glass to roll flat. Put pan into refrigerator. Chill until firm. Coating: melt chocolate chips and the butter or margarine in the sauce pan on low heat stirring often until smooth. Remove pan from refrigerator. Pour chocolate coating over the top of the squares in the pan using a rubber spatula to remove all of the chocolate. Let stand to set the chocolate. Cut into 36 squares or 18 bars.