The Service Pack 2 for Windows Vista is now available for public download on Microsoft Download Center. You may either download Vista SP2 as a standalone installer or as an ISO image for burning onto a DVD.
The installer for Vista SP2 (Windows6.0-KB948465-X86.exe) is around 350 MB but if you don’t want to download that big a file, wait until Microsoft pushes the SP2 patch via the Windows Update or Automatic Updates feature as that will only download the essential components.
An important point - you will be able to install Windows Vista SP2 only when your systems are already running Service Pack 1. Microsoft says that they chose not to offer a cumulative SP2 package this time to keep the file size under control.
If you’ve used vLite (or something similar) to slipstream Vista with SP1, you may receive certain errors while installing SP2 due to missing components. In that case, the best option is to either perform an in-place upgrade using your original Windows Vista DVD or reinstall Vista from scratch, then install SP1 followed by a file clean-up and then update to Service Pack 2. Hat tip Mary J.