What will Microsoft do about Support for Windows XP and Office 2003
PDF version
According to: http://support.microsoft.com/gp/lifeselectindex, official mainstream support will end April 14th 2009 for Windows XP and Office 2003.
Extended support is available until 2014 and 2012 respectively for paying customers.
More info: http://blogs.zdnet.com/microsoft/?p=2365&tag=nl.e539