I saw this post over at http://www.graburfork.blogspot.com/ and knew it would be perfect for summer bbq's.
1/3 cup butter
Scrub and cut potatoes into 1/2 inch disks. Leave the skin on for more flavor. Boil them for approximately 10-12 minutes until fork tender, but not falling apart. Drain water and put discs on a hot grill. Brush them with melted butter and sprinkle with garlic salt and pepper. Grill for 6-7 minutes on each side. Serve hot from the grill.