Have butter at room temperature. Cream butter, peanut butter and powdered sugar. Stir in Rice Krispies. Roll into 1 inch balls or dip out with candy dipper onto a dish. Place in refrigerator at least 2 hours or until completely chilled. Melt chocolate chips and dip 1/2 ball in chocolate and place on wax paper to harden. Remove from wax paper to covered container. Refrigerate. Makes about 3 dozen.