I’ve deployed another WSUS3.0, thought to post about it. This setup is very simple and easy and you just need to do some tweaks with Group Policy to add the existing desktop on the WSUS List or if you want to the Desktop Targeting.
Note : You must run the WSUS Wizard to choose how you want to setup the WSUS. You can define the criteria of pushing the patches on your network. You can setup the synchronization time to update with Microsoft server to avoid bandwidth choking during the working hours.
In order to target the desktops to a particular group in the WSUS you need to some tweaks in the AD. I’ll try to write on this. cheers:)