I'm specifically interested in Windows 2000/XP, but Vista/7 would be interesting too (if different).
I was thinking along the lines of task scheduling a batch file or equivalent on a daily basis.
EDIT: Sorry, I should have provided more info. The question pertains to 10 machines which I manually apply updates. I don't want to install the updates programatically, but just find out if there are updates ready to download/install (i.e. the update shield icon in the system tray is indicating this) using a batch or script. Thanks.
In the end, Windows SUS wasn't an option, so I'm using the following in a batch file conjunction with ActiveState ActivePerl (recommended):
perl -nle "print $_ if m/updates detected/i" < c:\Windows\WindowsUpdate.log
This might be crude or dirty, and might break in future, but it currently does what I need.
Thanks for all the ideas.