Finally Windows Vista Service Pack 2 is released and available for public download. After little long wait Microsoft make available Vista Service Pack 2, it was already available on torrent sites.
You can download Vista SP2 from Microsoft download center as a standalone installer & as an ISO. To install Vista SP2 you must have installed Vista SP1.
Size of Vista SP2 is around 350 MB. You can download Vista Service Pack 2 Standalone Installer from this direct download link for 32 and 64 bit OS.