For meatballs: In a large mixing bowl combine egg, bread crumbs, onion, oregano and salt. Add ground beef. Mix and then shape into 24 meatballs (around 1 inch diameter). Arrange meatballs on 15X10X1 inch baking pan. Bake at 350 degrees for 15 to 20 minutes. Drain well. Add to spaghetti sauce and simmer on low for 10-15 minutes while you prepare the buns. Combine melted butter and garlic salt. Open hamburger buns. Brush butter mixture on insides of top and bottom hamburger buns. Sprinkle both insides with shredded cheese. Toast in toaster oven cheese side up. Remove from toaster oven and add 4 meatballs per sandwich and enjoy! Makes 6 meatball sandwiches.