[CentOS] Adding an 'official' CentOS image to the Amazon EC2 (Electronic Compute Cloud)

I don't know if it's xen under the hood or not (not much experience
with this sort of thing).  However, 'xen' is mentioned in the
following link which I'm following so perhaps it is xen related:
http://docs.amazonwebservices.com/AWSEC2/2009-03-01/DeveloperGuide/index.html?ami-via-loopback.html

I'm not all the way through this link so I can't vouch for it's
utility but it's good thus far.

Jason