The "inquirer" seems to think so.
http://www.theinquirer.net/default.aspx?article=35110
I don't know what this will mean.
If trure, perhaps you can have a dedicated DX10 sys with XP to run FSX?
Keep in mid though that DX10 is not backwards compatable with previous DX10 versions and XP will not surport DX9 as well as DX10 as VISTA will.
P.S.
I posted this in the FSX fourm as it seems to concern primarily FSX users.