Finally, the long-awaited SP3 for XP has now been released to manufacturing and will soon appear in Microsoft's typical update channels.
Chris Keroack, IT Pro Evangelist at Microsoft and release manager for SP3, wrote in the TechNet forums that "we are happy to announce that Windows XP Service Pack 3 (SP3) has released to manufacturing (RTM). Windows XP SP3 bits are now working their way through our manufacturing channels to be available to OEM and Enterprise customers.
We are also in the final stages of preparing for release to the web (i.e. you!) on April 29th, via Windows Update and the Microsoft Download Center. Online documentation for Windows XP SP3, such as Microsoft Knowledge Base articles and the Microsoft TechNet Windows XP TechCenter, will be updated then. For customers who use Windows XP at home, Windows XP SP3 Automatic Update distribution for users at home will begin in early summer."
To an overview head over and download Microsoft's related literature