• Windows XP Service Pack 3 Timeline: Hit RTM milestone on April 21, 2008; released unofficially on April 29; finally arrived on Windows Update and Microsoft Download Center on May 6.
• Automatic Distribution: Over two months later, it was finally released via Automatic Updates (AU). Users with Windows Update set to "automatically download recommended updates" will receive it. Those not getting it automatically can use the Windows Service Pack Blocker Tool Kit.
• Build Details: The final build (5512) includes 1,073 fixes since Windows XP SP2 in August 2004. Worth checking out the SP3 release notes and MUI pack. Also, know what to do with your version of Internet Explorer before installing.