Although it was released to manufacturing on April 21, 2008, the third and last service pack for Windows XP has yet to make it to end users. Despite this, Microsoft has already made available the first update tailored on XP SP3. Update for Windows XP (KB942763) is designed to integrate with both Windows XP SP2 and SP3, and to tweak the Daylight Saving Time settings on the operating systems. Microsoft released KB942763 on the same day it RTM'd XP SP3, in an effort to correlate automatically the computer clock with the correct date in 2008, following the changes introduced via Daylight Saving Time laws in markets around the world.

"The update changes the time zone data to accommodate daylight saving time (DST) changes in several countries. This update also includes other DST-related changes, time zone-related changes, and settings-related changes. This is a cumulative update rollup that includes all the changes that were previously released in Microsoft Knowledge Base (KB) articles 928388, 929120, and 933360," Microsoft revealed.

Similar updates have been released for a range of operating systems in addition to XP SP2 and SP3, including Windows Fundamentals for Legacy PCs, Windows Embedded for Point of Service, Windows Vista and Windows Server 2003. Neither Windows Vista SP1 nor Windows Server 2008 have anything to do with KB942763. The Redmond company is offering additional information related to the time changes affecting its products via the Daylight Saving Time Help and Support Center.

"When you apply this update, you may receive the following message: 'Update cannot be installed as a newer or same time zone update has already been installed on the system.' This message indicates that you have already applied the correct update or that Windows Updates or Microsoft Update has automatically installed this update. No additional action is required to update the Windows operating system software," Microsoft added.

Update: Windows XP SP3 RTM Build 5512 available for download here.