The good folks over on the WSUS product team blog just published a great post on how to install WSUS 3.0 SP1 through Windows Server 2008 SP2 Server Manager. Check out their intro and direct link below:
By default, Windows Server 2008 SP2 includes the ability to install the Windows Server Update Services Role Service by using Server Manager. This role lets you use the MMC Server Manager snap-in and wizards to install, configure, and manage WSUS 3.0 SP1. This behavior is different from Windows Server 2008 SP1 where the administrator needed to install an update to Server Manager to be able to install WSUS as a Role.
To continue reading visit Installing WSUS 3.0 SP1 through Windows Server 2008 SP2 Server Manager
J.C. Hornbeck | Manageability Knowledge Engineer