Combine butter and garlic powder in a small bowl; stir until well blended. Split French bread in half lengthwise, and spread each cut side with butter mixture.
Place bread, cut side down, on grill. Grill 2 minutes and 30 seconds over medium coals or until golden brown. Turn bread, and grill an additional 2 minutes and 30 seconds. Cut into 3/4- inch slices, and serve hot.