In a small bowl, soak the bread crumbs in the milk. In a large bowl, mix the ground meat with the soaked bread crumbs, the onion, garlic, parsley, oregano, egg, salt and pepper.
Form the meat mixture into 4 large balls. In a deep nonstick skillet, heat 2 tablespoons of olive oil. Add the meat balls and cook over moderately high heat, turning occasionally, until browned all over, about 7 minutes. Add the marinara sauce to the skillet; cover and simmer over low heat for 30 minutes, until the meatballs are cooked through. Serve over cooked spaghetti.