Man, it's cool. I'd never heard of it before, but this is a nifty trick that doubled my shooting speed without expanding my groups. Range Report on this tomorrow, but basically it goes like this:
1. On the firing line, with your pistol pointed at the target, take up the slack on your trigger. This is your reset point.
2. Squeeze the trigger the rest of the way to fire the gun. Do NOT let the trigger all the way out. Instead, let your trigger fingermove back to the reset point. The pistol is ready to fire again.
It's possible that some pistols with little slack won't benefit from this technique (i.e. there's very little distance between the reset point and the break), but the Glock I shot had rather a lot of slack. I'd expect a 92 would benefit a lot as well. 1911, maybe not so much.
It seems that this technique of minimizing the movement of your trigger finger reduces the opportunity for that movement to move your aim point off. If you're a particularly good marksman, this might not be very much use at all - you already have the muscle memory to keep this from happening. But for a duffer like me, it was nothing short of astonishing. My moderately fast groups ("shoot once a second") were no bigger than my slow groups ("take all the time you want").
Report and pictures tomorrow, but I have to get the boys fed. But man, I'm doing this again.
UPDATE 16 February 2011 15:01: Updated post with pictures here.