I thought some might find these images of HIGH SPEED PHOTOGRAPHY fascinating. (Seems a tad destructive unless you are a CSI, lol). If you continue to the next page, there are some wonderful images of droplet photography too.
I had a dig around after taking a look at some of those pics yesterday. Apparently some cameras support something called FP flash mode (Google link) that will synch at high speeds.
It looks like there are some significant gotchas - particularly reduced flash output and effective range. For the kind of pics shown in the link above I doubt that's an issue though.
It's not supported on my D40 but looks like it is on the D80 I'm buying to replace it. I'll have to have a play...