Cook shells according to package directions.  Drain and rinse with cold water.  Meanwhile, in large skillet cook meat, onion, sweet pepper, and garlic until meat is brown (drain if necessary).  In a medium bowl, combine bread crumbs, fennel seeds, salt, and pepper.  Add the meat mixture and 1/4 cup of the spaghetti sauce; mix well.  In a 9x13 baking dish, pour a little bit of the spaghetti sauce.  Spoon about 2 tbsp. of the meat mixture into each shell and arrange in dish.  Pour the remaining sauce over the filled shells.  Cover with foil and bake at 375 for 40 minutes.