Sorry, I should probably have checked that link.
I know that the Dutch forces are going to control some desert area in the south of Iraq, and are in command of that area. I would assume they're still under the command of the US generals, though - it'd be a bit silly if they were not. If they ever get attacked, they're pretty much dependent on US/UK support, after all; and we would *not* want the situation we had in Bosnia, where the vague UN command structure meant we were left without such support.