Microsoft has released Service Pack 2 (SP2) for Windows Vista and Server 2008. Service Pack 2 for Windows Server 2008 and Windows Vista (SP2) is an update to Windows Vista and Windows Server 2008 that supports new kinds of hardware and emerging hardware standards, and includes all updates delivered since SP1. SP2 simplifies administration by enabling IT administrators to deploy and support a single service pack for clients and servers.
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. By providing these fixes integrated into a single service pack for both client and server, Microsoft provides a single high-quality update that minimizes deployment and testing complexity for customers.
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.
Also if you have any beta versions of SP2 installed, they must be uninstalled prior to installing. Use the Control Panel applet "Programs and Features" and select "View installed updates" from the top left of the task pane and look for KB94846.
Its a standalone installer and available for both 32-bit and 64-bit versions.
You can download SP2 using following links: