Service Pack 2 for Windows Vista and Windows 2008 Final Release

Service Pack 2 (SP2) for Windows Server 2008 and Windows Vista is an update to Windows Vista and Windows Server 2008. It provides customer and partner feedback-driven fixes into a single service pack, minimizing deployment and testing complexity. In addition to all previously released updates since SP1, SP2supports new types of hardware, and adds support for several emerging standards.

Download : Windows Server 2008 Service Pack 2 and Windows Vista Service Pack 2 - Five Language Standalone DVD ISO (KB948465)

Download : Windows Server 2008 32-bit Service Pack 2 and Windows Vista 32-bit Service Pack 2 - Five Language Standalone (KB948465)

Download : Windows Server 2008 Service Pack 2 and Windows Vista Service Pack 2 - Five Language Standalone for x64-based systems (KB948465)

Download : Windows Server 2008 Service Pack 2 - Five Language Standalone for ia64-based Systems (KB948465)

News source : Microsoft

Or instead of using the links in the posts above just run the Windows Update application that comes with Vista and will install SP2 for you.