In a large bowl, combine bread crumbs, pork, beef, parsley, egg, onions, oregano, salt and pepper. Mix briefly with your hands. Form the mixture into 2-inch balls and transfer to a large plate. Heat oil in a large skillet over medium high heat until hot but not smoking. Add meatballs and cook until browned, about 4 minutes. Transfer to a paper towel to drain. Discard oil in skillet, then add pasta sauce and bring to a simmer over medium high heat. Add meatballs, reduce heat to medium low, cover and simmer until cooked through, about 20 to 25 minutes. Meanwhile, cook spaghetti according to directions on package. Drain well and transfer to a large bowl. Top spaghetti with sauce and meatballs and sprinkle cheese over the top.