Microsoft today launched the final version of Windows Vista Service Pack 1 (SP1). The first major update to the Windows Vista operating system was released to manufacturing (RTM) and will be posted for download - at least in part. Windows Server 2008 was also publicly announced earlier today.

UPDATE: Click here for full details of the Vista SP1 release, plus the timescale of the rollout and when you can buy a brand new Vista SP1 PC.

The Windows Vista SP1 release means that computer makers will receive media later in the week to install the updated operating system on new laptops and desktops. Bits of the update will also be posted for download today.

It is expected that today's download launch will include just five of the 36 available language packs - English, French, German, Japanese and Spanish. The second wave - according to reports slated for 'one-to-two weeks later' - will include all 36 language packs.

See also:

Windows Vista: the definitive review

Windows Vista SP1 Release Candidate review

Happy birthday Vista? Perhaps not...

Previously, Microsoft has said it would break SP1 into two standalone installers for businesses: a 450MB package that includes the five packs and a 550MB installer that offers 36 languages. Both are expected to be available for download from Microsoft's website.

SP1 will also be offered to users through Windows Update, Microsoft Update and presumably Windows Server Update Services (WSUS). That update will weigh in at around 65MB. Microsoft explained the smaller size in a change log posted to its support site: "Windows Update... utilises an efficient transfer mechanism to download only the actual bytes changed."

Microsoft last issued an SP1 build on January 24, when it updated the code offered to an invite-only group of approximately 15,000 testers. That build, along with one the week before, gave credence to accounts that SP1's pace had quickened, and that the service pack's release was imminent.

Microsoft repeated Saturday what it has said all along: Vista SP1 would go final in the first quarter of 2008, which ends March 31.

"We are targeting to deliver SP1 RTM in Q1 CY08," a spokeswoman wrote in an email. Representatives of the Windows Server team, however, were not available for comment.

The company has previously announced plans to launch Windows Server 2008 on February 27 at an event in Los Angeles.