Redmond plans to shelve its support of XP in June 2008, by which time it should have pumped out Vista service pack one (SP1) to the masses. But NEC will continue to supply the XP reversal tool for anyone wanting to use it.
Only in the M$ world would you be grateful for a vendor supplied tool to put the seven year old OS of your choice onto a machine. See this Techworld article for details. Better yet, make yourself a Linux install and forget licensing forever.