In 1 1/2 quart micro-safe casserole, cook cream cheese on HIGH about 1 minute or until soft. Stir in sour cream, milk, mayonnaise, and Worcestershire sauce. Add the kielbasa, half of the onion and Parmesan cheese; stir. Cook, uncovered on HIGH 3 to 4 minutes or until heated through, stirring once. Sprinkle with remaining onion. Serve with crackers, vegetables or rye bread. Makes 2 1/2 cups.