Is there a way to remove the uninstall files created when
a Vista update is installed? They take up increasing amounts
of disk space as time goes on and this will impact disk
performance. Nor are they, generally, needed after a period
of time.

The files could be removed manually under XP, but they are
in a different place in Vista. I have seen as much a a GB of
the update uninstall files in an XP installation so the amount is
not trivial after a while.