Here's a link about it -> http://www.lockergnome.com/news/2012/09/06/windows-8-xp-mode/
And one more -> http://lifehacker.com/5965889/how-to-run-windows-xp-for-free-in-windows-8
Hope this answers and helps you along,
With 7 you had to have "Pro" to get compatibility with old versions of Windows.
Is that not the case with Windows 8? Is compatibility mode available in all (non-RT) versions?