i took a riding class last summer with dave wood, a fairly decent rider from norcal, and we worked on this technique. basically, the front brake helps weight the front tire, increasing traction. it also compresses the fork, thus shortening the wheelbase and changing the front-end geometry for quicker turnin. as you get to the apex, you should be looking where you want to go, and easing off the brake and rolling on the throttle at the same time. it's amazing how well the front wheel will stick in a corner when you start to get comfortable with this technique.
if you squeeze the brake too hard, you will know. you pretty much only have until the fork starts rebounding to get your initial turning done, so i apply more pressure gradually, so the weight on the front tire keeps increasing, if that makes sense.
after a few weeks of practice with this technique, i suddenly found myself going MUCH faster, and i was no longer washing the front wheel unexpectedly. i still do a figure-8 drill sometimes. just grab a few rocks or logs or something and put them 30' apart or so, and practice doing figure eights around them, and trying to make it as smooth and fast as possible.
mw