There's a shareware tool called Update Cleanup that makes it easy to delete these $NtUninstallKB Service Pack / Patch folders and clean up the related Registry entries at the same time. Although it is not free, you are given a lengthy free trial which is more than enough time for you to clean up these folders.
You can find a copy at:
http://shareware.us/update.htm
I've used it for several months now and it seems to work fine.