This tip can be nice for those that doesen't have remote GUI control over their computer. Add this line to your .profile file, in your home directory:
softwareupdate --list
When you log in, you'll see:
Welcome to Darwin!
Software Update Tool
Copyright 2002-2003 Apple Computer, Inc.
Your software is up to date.
www:~
To install an update if softwareupdate finds out-of-date packages, type softwareupdate -install packagename
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040207051813711