There was recently a history of that in one of major Lithuanian magazines (8 pages), "World Disasters" section (also short interview with Soviet general, who ordered to shoot down plane). So, I have to correct everything:
-Korean plane wasn't cutting flight time. Pilot forgot to turn on some system (GPS I believe) and plane didn't followed the predefined course, instead, he taken shortest course from Anchoridge to Seul.
-Plane flew with nav lights on. The pilots first didn't shot down plane because of that (they though it may be An124 I believe). However, when plane didn't responded for half an hour and Soviet civil flights control (twice asked) answered that there should be no civil flights in region, general ordered to shoot down the plane.
-747 was in Japanese frequency, because they had to flew over Japan at a time.
-One 747 a year ago also was ordered to land by Soviets, but they somehow heard that (or just seen fighters on tale) and landed on iced lake in Syberia.
-USA is also responsible for the incident, because 747 flew over US base and US pilots definately seen it. USA didn't told that to 747 because they wanted to see, how Soviets will react, etc. Such trying was important in cold war. Also, later they could use the shot down flight as propaganda.
-Soviet General who ordered to shot down plane said, that he would do the same now if the same reasons would arise. I believe he still works in military.
-After missile aircraft remained airporn for few minutes, but it only could take-off (nose up), not land (because of damaged hydraulic by the heat-reacting missile). It reached height limit and exploded.
-There is a movie made about this tragedy
-This was not the only shot down plane. US ship also shot down Iran Air A300, Ukrainians shot down Syberia Tu-154, some people believe that TWA 747 back in 1994 was also shot down.