1. Mix pudding according to package directions, except use 3-1/3 cups milk. Beat in peanut butter.
2. Line a 9x13 pa with half grahm cracker squares. Three crackers will have to be cut in half to fit.
3. Spread pudding mixture over grahm crackers. Top with remaining crackers.
4. Freeze for four at least hours. Cut into squares and remove from pan. Store in freezer in plastic bag.