Sometimes it is desired to set Windows Update on client devices to look at Microsoft Update instead.
Through the GUI this will take some clicks, where I would always like to automate these things…
This can be done either by setting a registry key, or you could just use a script.

Registry
Registry key: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\PendingServiceRegistration\7971f918-a847-4430-9279-4a52d1efe18d
Registry name: ClientApplicationID (REG_SZ)
Registry value: My App

Registry key: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\PendingServiceRegistration\7971f918-a847-4430-9279-4a52d1efe18d
Registry name: RegisterWithAU (REG_SZ)
Registry value: 1

Script (VBS):
Set ServiceManager = CreateObject("Microsoft.Update.ServiceManager")
ServiceManager.ClientApplicationID = "My App"
‘add the Microsoft Update Service, GUID
Set NewUpdateService = ServiceManager.AddService2("7971f918-a847-4430-9279-4a52d1efe18d",7,"")

This post is based on: http://msdn.microsoft.com/en-us/library/windows/desktop/aa826676(v=vs.85).aspx