After renting the helicopter from a flight school, the pilot took off and flew to a nearby town where he picked up two passengers. He then flew them to another town to attend a party. During the flights everything was normal. Upon arrival at their destination, the pilot began to circle and asked one of the passengers to call a friend who was on the ground on his cell phone, to check the landing area to make sure it was clear for him to land. After the pilot was told it was "clear for landing," he started a smooth descent "with all of the instruments in the green arc," to the landing area which was located on a dirt road on the ridge of a mountain. The landing was smooth and the pilot touched down lightly on the skids. While the helicopter had not fully set down and was still light on the skids, he began to check the "balance of the helicopter" before setting the collective to the full down position. When he moved the cyclic forward, the helicopter pitched forward. Then when he moved the cyclic aft to its previous position, the helicopter pitched aft and he heard a "big noise" and felt a vibration. He immediately "pulled" collective and rolled the throttle to the full throttle position to get the helicopter back into the air but, the helicopter started to spin clockwise and he could not stop the rotation, even with the application of full left pedal. He then leveled the helicopter while it was still spinning and tried to make it back to the landing site but, there was not enough power to keep it airborne. The left skid then contacted the ground and the helicopter rolled over on to its left side. Postaccident examination of the helicopter by a Federal Aviation Administration inspector revealed that the tail rotor assembly and tail boom were substantially damaged.