The airplane was parked at a gate and boarding passengers, when it was struck on it's right side by a catering truck. Damage to the fuselage included a 6-inch, by 14-inch puncture, and several small dents. In addition, two formers and one stringer were damaged. The driver of the catering truck reported that he was approaching the airplane, when he received a radio call. While talking over the radio, he inadvertently stepped on the accelerator, and the truck subsequently struck the airplane.