Singapore Airlines will on April 6th 2012 will operate its last Boeing 747 service, flying a special commemorative flight between Singapore and Hong Kong. Singapore Airlines will operate special commemorative flights between Singapore and Hong Kong on 6 April 2012 to mark the retirement of the Boeing 747 after nearly four decades of service.

Flight SQ747 from Singapore to Hong Kong and SQ748 from Hong Kong to Singapore will be operated with the B747-400, replacing existing flights SQ860 and SQ863, which are normally operated with Airbus A330-300s.

The special flights, which will be SIA’s last commercial passenger services with the B747, are now open for sale. In addition to more than 300 commercial passengers, on board will be employees who have worked on the aircraft throughout its storied history, as well as a group of underprivileged children and media.

The last regular flight will be between Melbourne and Singapore on March 25th 2012.  This services will be flown by a B747-400 aircraft. As recent as March 2003 Singapore Airlines operated 51 Boeing 747 aircraft. 

http://www.singaporeair.com/jsp/cms/en_UK/press_release_news/ne120217.jsp for Singapore Airline media release.