I have a PowerBook G4 from 2004 with that keyboard shortcut, so it's nothing new. However, I currently use a similar utility called SleepDisplay in conjunction with Spark to put my desktop's display to sleep when I hit the F19 key in the very corner of my keyboard. It's more convenient than the three-key equivalent.

I don't see why this is necessary (anymore). Maybe this feature wasn't in place in 2006, but now you can press Control-Shift-Eject to cause the display to go to sleep. Thought this might help anyone still wondering how to do this.

I use this nightly on my iBook; perfect for listening to audiobooks or tunes as you go to sleep.

i still use this nearly every night, and haven't found another product that does quite the same thing. it also lets me leave my computer running guilt-free if i go out during the day. ... remember Apple's own warning: "Never allowing your display to sleep my shorten its lifespan."

i recommend combining this app with Quicksilver for fast launching.