New information has leaked about Windows XP Service Pack 3, revealing that Microsoft has debuted the testing stage of the refresh. The third service pack for Windows XP has had everything but an easy ride. Announced initially for 2005, XP SP3 was delayed into 2006 and then further postponed for later that same year. Going head to head against the release of Windows Vista, XP SP3 was pushed into 2007 only to get yet another preliminary release date all the way into the first half of 2008. Up until this point there was little information available on XP SP3, outside of the availability date and a few anodyne details about its contents.

Still, Microsoft did slip up earlier this year and announced that Windows XP SP3 would ship by the end of 2007. The Redmond company then denied the validity of the information blaming a spelling error for the promise of XP SP3 in 2007. Microsoft only confirmed the preliminary availability date set for the first half of 2008. However, the company is already testing the third service pack for Windows XP. According to AeroXP, Microsoft shipped Windows XP SP3 to testers concomitantly with the release of Windows Vista Service Pack 1.

Under the Windows Omerta strategy imposed by Steven Sinofsky, Senior Vice President, Windows and Windows Live Engineering Group, XP SP2, just as Vista SP1 Beta, was made available to a limited and select pool of testers. Windows XP SP3 is build 5.1.2600.3180 (xpsp.070718-2058) and weighs in at 350MB, including resolves for in excess of 900 problems already addressed through a variety of standalone hotfixes released after SP2. The images included at the bottom claim to be screenshots taken from Windows XP SP3, courtesy of WinBeta.

The launch date for the final versions of Windows Vista SP1 and Windows XP SP3 are only speculations at this point. Microsoft only confirmed that Vista SP1 beta will be delivered to the public by the end of 2007 and that XP SP3 will drop in 2008. But the obvious proximity of the testing builds for the service pack for XP and Vista could possibly point to a joint release, either by the end of this year, or in 2008.