I, too, can vouch for the Trattoria Milanese (Via Santa Marta 11 - ask for directions, it's on a hard-to-find alley near the Duomo). Very good osso bucco and risotto Milanese style, and great pastas. It is also inexpensive (about $40/pp for appetizer, entree and dessert). Best yet, the entire menu is in Italian and the waiters can help you with English translations and recommendations if you prefer