Supposedly Microsoft was supposed to stop all sales of Windows XP in March ‘o7. They changed that date to June ’07, then December ’07, then July ’08, December ’08, June ’09, and now it appears it might get extended to April ’10 if the following article has any substance to it.
Microsoft first released XP in September 2001. When they released Vista in February 2007, they pulled XP from selling in any retail outlet, but allowed customers to continue buying it through online retailers like Dell, HP, and a few others. Because of the severe lashing Vista has received over the last two years, Microsoft continued to allow these vendors to sell XP as a downgrade from Vista.
Read more about this store in this ComputerWorld article.