Beat together cream cheese and confectioners' sugar. Mix in peanut butter and milk. Beat until smooth. Fold in whipped topping. Spoon into two 9 inch graham cracker pie shells, and carefully pour 3 circles, one right outside the other, on the top of the pie with chocolate sauce. Next, take a toothpick, insert it into the center about half an inch deep, and draw lines going out to the edge of the pie. Make these lines all the way around, each time starting from the center and drawing out. It will create a fun spider web design on the top of your pie! Cover, and freeze until firm. Cut, serve, and enjoy!