2009 05 27 Vista SP2 up and running.
Microsoft has released the standalone installers for Service Pack 2 for Windows Vista and Windows Server 2008. This is a consolidated installer for both products. There are both 32-bit and 64-bit versions available. HERE
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.
If I installed a Release Candidate of SP2, can I simply upgrade it to a release version? No. Pre-RTM builds are not upgradeable. If you have not run the Service Pack cleanup tool after installing a pre-release version of SP2, you should be able to uninstall the pre-release version, and then do a full install of the released version.
Notable Changes in Windows Server 2008 SP2 and Windows Vista SP2