As I noted the other day in my post Thinking about downloading SP2 for Windows Vista or Windows Server 2008? Please download it from a trusted source, I'd seen several third party sites offering downloads to Service Pack 2 (SP2) for Windows Server 2008 and Windows Vista. As I wrote here, you should only download software from a trusted source – via Microsoft – and avoid peer to peer to save yourself the security risk.
As the MU team posted here, Windows Vista and Windows Server 2008 Service Pack 2 will be available in the coming weeks on the Download Center (DLC) and also through Windows Update and WSUS.
That would be today, according to Brandon's latest post on The Windows team blog…
On April 28th, we announced that Windows Vista and Windows Server 2008 (Service Pack 2) SP2 had RTM’d. Today, we are pleased to announce the Release to Web (RTW) for Windows Vista and Windows Server 2008 SP2.
Windows Vista and Windows Server 2008 SP2, a combined service pack for both operating systems encapsulated in a single installer, will simplify deployment, management, and support for IT Professionals. It includes support for new types of hardware and emerging hardware standards, as well as updates since SP1. For specific information on what’s included in SP2, visit the notable changes document.
Windows Vista and Windows Server 2008 SP2 is now available for download on the Microsoft Download Center and on Windows Update.
I agree with Brandon: As I've said before, visit Windows Update, or make sure Automatic Update (AU) is turned to get the latest service pack on once it goes live to AU. You can visit the Microsoft Download Center to get SP2 or use Windows Update (WU) to install SP2, but the easiest way is to turn on Automatic Update (AU) and your computer will automatically download and install SP2 beginning via a "throttled release" schedule in June. There's certainly no harm in using WU today, and this is easy for individual users. IT Pros should download the bits from the DLC and install accordingly.
Also available via http://bit.ly/7na8b