Line 2 cookie sheets w/ waxed paper. Beat peanut butter,butter and vanilla. Gradually beat in sugar and flour until well blended. Roll rounded teaspoonfulls into i inch balls. Arrange on the cookie sheets and refrigerate 1 hour or so til firm. Spear w/ a toothpick and dip in chocolate covering 2/3 and replace on the the cookie sheet chocolate side down, refrigerate again fro 15 min until firm. Store tightly covered in the fridge up to 2 months.