Question: I’ve got Windows XP and would like to stick with it. How long will Microsoft support XP? Will I get herded into a Vista upgrade at some point?

Answer: Microsoft may be putting all its marketing resources
behind Windows Vista, but Windows XP has plenty of life left in it. The company
is working on a third service-pack update for XP, which it plans to ship in
the first half of 2008.

Elsewhere on its site (http://support.microsoft.com/lifecycle/?p1=3221), Microsoft
says "mainstream support" for the Home Edition of XP, meaning continued
development of security fixes and other patches, will stop April 14, 2009. "Extended
support," in which it will only release security updates, will end April
8, 2014.

Source: Washington Post