The 8,000-hour commercial pilot lined up the airplane on final approach for runway 35L at his destination airport, following an IFR cross country flight. The pilot stated during an interview with a Federal Aviation Administration (FAA) inspector that he forgot to lower the landing gear while on final approach. The aircraft touched down with the flaps fully extended and skidded on the runway for approximately 1,150 feet. The pilot, sole occupant of the twin engine airplane, was not injured. An examination of the airplane by an FAA inspector revealed that when the aircraft was lifted on to jacks and the master battery switch was turned on the landing gear horn was clearly heard. The landing gear handle was then selected to the down position and the gear extended to the down and locked position with three green lights observed. At the time of the accident, the weather was reported as winds from 070 degrees at 9 knots, visibility of 10 miles, temperature 27 degrees Celsius, dew point 19 degrees Celsius, and an altimeter setting of 30.27 inches of Mercury.