Sure.
First off. Check the manuals because I may not be entirely correct, but here is what I did (and I believe d70 will do this exact mode, too).
First, go into the custom setting menu on the D70 and make sure you enable "FP high speed flash synch"--this allows your SB800 to synch (albeit with a little less power than usual) all the way up to your fastest shutter speed. I set mine up to do this mode whenever the shutter will be faster than 1/250th.
THEN, when your SB800 is on-camera and turned on, just scroll with the mode button until you see both FP AND BL.
Goof around a bunch before the big event (I encourage you to also to use histograms after you shoot, then play with compensation on BOTH the camera and the flash to get the balance to your liking in each and every situation).
Once you get the settings turned on, its just a matter of practicing and seeing what looks good. I am amazed at the results that this flash/camera combo can give.
Hope this helps.