Heat broiler. Put skewers in a dish of cold water to soak so they do not burn during broiling. Cut peaches in half, using indentation on one side as a guide. With both hands, give a quick, sharp twist to halves to loosen them from the stones then cut in quarters. Hull strawberries, washing them first only if sandy. Drain skewers. Thread 3 strawberries and 4 peach quarters alternately onto each skewer. Brush kebabs generously with melted butter and roll in sugar so fruit is thoroughly covered. Arrange kebabs on a broiler rack lined with foil. Broil about 3 inches from the heat until fruit is tender and caramelized, turning once, 4 to 6 minutes on each side. Serve hot or warm with the accompaniment of your choice.