Cut pork tenderloin into 3 inch cubes and place in shallow dish. Melt butter in saucepan and add remaining ingredients. Bring to a boil and simmer 5 minutes. Pour over meat. Cover and leave overnight in refrigerator. Turn meat periodically (butter will congeal but don't worry).
Remove meat from marinade (reserve) and put 5 or 6 pieces on each skewer. Grill on barbecue for 15 minutes or until done (don't over cook). Turn frequently - will keep in warm oven until dinner is served - but best straight off the grill.