Quick update on Windows Vista SP1’s availability to WSUS. As I mentioned previously, we are planning on making the full standalone version of the service pack directly available to WSUS shortly (it’s been available for the last couple months in the MU catalog). Before we do so, we would like to give you one last reminder to install the WinVerifyTrust update (KB 938759) if you are running your WSUS server on a Windows 2003 Server or else approving SP1 will result in the binary being continually re-downloaded to the server.
Check out the Windows Vista Service Pack 1 Deployment Guide or Windows Vista Service Pack 1 TechNet site for more information about SP1, or read KB 948343.
WSUS Program Manager