Delete partially downloaded OS X Update?

[Jr2Jr]

I started downloading the OS 10.6.4 update along with a few other software updates via my mac's Software Update. Then decided not to do it in case my IT admin has stuff on my computer that isn't compatible so I canceled it. I was able to go to my system/library/updates folder to delete the other stuff I had downloaded so that they won't install when I restart. But every time I open Software Update it still says "Mac OS X Update: Partially downloaded (21%)."
I haven't shut my computer down yet.

Where is it partially downloaded to? And how could I get rid of all remnants of it?

Thanks.

BTW, in case it makes a difference, I'm on a MacBookPro i7 with OS 10.6.3.