Cut peppers into 1/2-inch strips. Put eight sausages in saucepan, cover with water, bring to boil, then simmer for five minutes.
Drain off water and dry sausages, thoroughly with paper towels.
Heat oil in heavy frying pan, add sausages and brown well on all sides; remove sausages from pan, set aside. Add onion and peppers to pan, saute until lightly browned, then add oregano, garlic, tomato sauce, salt and pepper. Bring to boil, then return sausages to pan and simmer all for 25 minutes.