Microsoft has the Service pack 2 for Windows 2008 and Windows Vista available for download.
SP2 is an update to Windows Server 2008 and Windows Vista that incorporates improvements discovered through automated feedback, as well as updates that have been delivered since SP1. Service Pack 1 is a prerequisite for installing Service Pack 2. Please make sure that your system is running Service Pack 1 before you install Service Pack 2.
Service Pack 2 for Windows Server 2008 and Windows Vista on Technet