From SANS: http://www.sans.org/newsletters/newsbites/newsbites.php?vol=10&issue=52&rss=Y#sID312

Microsoft Retires Windows XP, Will Support OS Through 2014 (June 30, 2008)
As of July 1, Microsoft will no longer be making its Windows XP operating system available to computer makers or consumers. XP will still be made available to small, independent computer makers through July 2009, and to manufacturers of low cost computers such as Asus until 2010. Some manufacturers are taking advantage of a loophole in Microsoft's licensing agreement that allows users to downgrade to earlier versions of operating systems at no cost. The decision to discontinue XP has met with protests from users who are unhappy with Windows Vista. In response, Microsoft has recently announced that it will support Windows XP through 2014.


http://www.informationweek.com/news/windows/operatingsystems/showArticle.jhtml?articleID=208801694