Microsoft announced on Wednesday that they have begun to deliver Windows Vista Service Pack 1 via an automatic update. Windows Vista SP1 will be automatically downloaded and installed on machines who have Windows Update. Starting first will be important patches, hotfixes, and other updates which will be sent via automatic updates. From there, Microsoft will begin to automatically distribute Vista Service Pack 1.
A Microsoft spokeswoman stated "Today, Microsoft will begin automatic distribution of SP1. This means the users with the Automatic Update feature turned on will automatically download SP1 to their PCs."
While all customers will not receive Vista SP1 immediately via Automatic Update, there's no time line offered as to when they would all receive it eventually. Microsoft claims to have opted for staggered distribution to prevent mass occurrence of driver incompatibility and other such issues. The automatic delivery will be rolled out to English, French, German, Japanese, and Spanish versions first.
Source:→ Half Life Source