Cook sausage in frying pan on medium heat until browned and crumbly. Drain well. OR Cook sausage whole in casings; remove and dry, then cut into halved circles. Place in crock pot (use a liner for easy clean up). Add tomato sauce and diced tomatoes. Add oregano, garlic powder, salt and pepper, oil, sugar and stir well. Cook on low 7-8 hours or high 4-6 hours. (I've found that 4 hours is plenty). Salt large pot of water and cook penne 4-5 min. less than directions on box call for (about 7-8 min.). Add penne and stir well. Top with 1 cup shredded cheese. Continue to cook on high for 15-20 min. or until past is tender and heated and cheeses melted. Serve w/ Parmesan cheese.