The service pack includes all security updates, out-of-band releases, and hotfixes released since Windows XP SP2 hit Microsoft's servers back in August 2004. At the same time though, every service pack Microsoft releases is cumulative; it is possible to install just SP3 on a clean install of XP.

In addition, SP3 will bring some Vista features to XP users, including Network Access Protection, "Black Hole" Router Detection, the Microsoft Kernel Cryptographic Module, and the ability to install XP without entering a product key.

Windows Internet Explorer 7 must still be downloaded and installed separately. There are also reported speed improvements for the six-year-old operating system.

Go here to download more information about Windows XP Service Pack 3 from Microsoft.