Preheat oven to 350 degrees. Cook sausage in large skillet over medium-high heat about 5 minutes or until no longer pink, stirring to separate.
Combine sauce, sausage, ricotta cheese, noodles, half the mozzarella cheese, mushrooms and bell pepper in large bowl. Spoon into a 3-quart casserole dish or 13 x 9 baking pan. Top with remaining mozzarella cheese.
Bake, uncovered, about 25 minutes or until heated through.