In A Small Bowl, Beat The Cream Cheese, Mayonnaise And Parmesan Cheese Until Blended. Stir In Spinach And Mozzarella Cheese. Spoon Into An Ungreased Microwave-Safe 9-In. Pie Plate. Microwave, Uncovered, On High For 4-5 Minutes Or Until Bubbly, Stirring Twice. Serve With Crackers Or Vegetables.