So finally the much awaited Windows XP Service Pack 3 is now officially available! The latest version includes all previously released updates for the operating system. This update also includes a small number of new functionalities, which do not significantly change customers’ experience with the operating system. If you're expecting Vista look in the SP3 then you're in for a disappointment as Microsoft is not adding significant Windows Vista functionality to Windows XP through SP3. However, SP3 does include Network Access Protection (NAP) to help organizations that use Windows XP to take advantage of new features in the Windows Server 2008 operating system.
[Product Page, Release Paper (pdf)]