CHANGE SUS ADDRESS ON LEOPARD CLIENTS

If you have a Software Update server somewhere on your network you can use MCX to force clients to use it. But what about clients that aren't bound to Open Directory? Time to bring up the Terminal to manually change the update server.

It's probably a good idea to make a backup first:
sudo cp /Library/Preferences/com.apple.SoftwareUpdate.plist /Library/Preferences/com.apple.SoftwareUpdate.bak

Now make the changes:
sudo defaults write /Library/Preferences/com.apple.SoftwareUpdate CatalogURL 'http://<software update server address>:8088/'

Start Software Update and if you're successful you should see your server name in brackets on the Software Update window title.

NOTE:
Software Update may not work if the server address you used is different to what is referenced in the SU Catalog (say you used myServer.local instead of myServer.myDomain.com). You can find out what address the SU Catalog is using by viewing the catalog in your browser:
http://<software update server address>:8088/index.sucatalog