In a large skillet cook meat, onion and green pepper until meat is brown and vegetables are tender. Drain off liquid, then stir in tomato sauce and salt and pepper. Cook noodles. In a small bowl combine cheeses and yogurt. Toss mixture with hot, cooked noodles. Layer half of the noodle mixture into a 9x13 inch cxasserole. Spoon meat over center. Layer remaining noodles over meat. Cover and bake at 375� for 30 minutes. Uncover and bake another 10-15 minutes or until bubbly.