Preheat oven to 350 degrees F. In small bowl, cut peanut butter into confectioners' sugar until crumbly; sprinkle into pie crust.
In large saucepan, mix sweetened condensed milk, egg yolks, water and pudding mix; cook and stir until thickened. Cool slightly; stir in sour cream. Spoon into prepared pie crust.
In small bowl, beat egg whites with cream of tartar with electric mixer until soft peaks form. Gradually beat in sugar, 1 tablespoon at a time; beat 4 minutes longer or until sugar is dissolved and stiff glossy peaks form.
Spread on pie, sealing carefully to edge of crust to prevent meringue from shrinking.
Bake for 15 minutes or until golden brown. Cool. Chill. Store leftovers covered in refrigerator.