Windows XP users have started receiving SP3 via Windows Update today. Microsoft has also provided instructions on how to remove it, if it results in instability.According to Microsoft, "Windows XP Service Pack 3 (SP3) includes all previously released Windows XP updates, including security updates and hotfixes. It also includes select out-of-band releases, and a small number of new enhancements, which do not significantly change customers' experience with the operating system." Among the latter is Network Access Protection (NAP), which will help XP users work with Windows Server 2008.
For those who experience instability or changed functionality after installing SP3, this page describes four techniques for removing it.The Inquirer