Microsoft Update Team: Windows XP Service Pack 3 (SP3) is now available on Windows Update (and the Microsoft Download Center)!
If you'd like to install it via WU today, you'll need to visit the Windows Update website. To do this, go to Windows Update and perform an express or custom install, make sure you see the service pack selected, and proceed with the install. After it downloads, you'll see a series of screens and you'll be asked to make a few clicks before the install will begin.
If you're not in a rush, we recommend you use Automatic Updates to install Windows XP SP3. It provides the best experience because the download will happen in the background. We're planning to begin automatically distributing Windows XP SP3 over AU sometime in the next few months.
Windows XP SP3 Downloads | Full Article
Microsoft, Windows XP, SP3, XP SP3, Windows Update, Download