The primary difference between regular pork sausage and Italian sausage is "in the spices". Breakfast sausage or regular pork sausage's main flavor is derived from sage, while Italian sausage's main flavor is derived from fennel.
Both sausages are made of pork and traditionally stuffed into casings; pork sausage is stuffed into sheep casings and Italian sausage into hog casings. Check out recipes here.
In sausage news, a Northern California company started by the family that opened fast-food chain Lee’s Sandwiches International, Inc. has issued a recall of 740 pounds of dried sausage products that may be contaminated with dangerous toxins. Find out more at Forbes.