Preheat oven to 400°F. Spray a large skillet with nonstick vegetable oil spray. Brown sausage thoroughly on all sides; continue to cook until sausage is thoroughly cooked. Remove and slice sausage, drain fat. In the same skillet, saute onion and peppers until tender. Return sausage to skillet; add sauce. Cover and simmer until heated through. Meanwhile, horizontally slice and remove the top third of Italian bread loaf. Hollow out bottom of loaf, leaving a 3/4" shell. Place on baking sheet; fill with sausage mixture. Evenly top with cheese. Bake 15 minutes or until bubbly. Place top of bread on loaf. Slice into wedges.