Lxlabs HyperVM is a multi-platform, multi-tiered, multi-server, multi-virtualization web based application that will allow you to create and manage different Virtual Machines each based on different technologies across machines and platforms.
Xen Source Cool Configurations is a blog / wiki of some of the coolest Xen configurations around !
provide a variety of downloads and howto’s to facilitate use of the Xen Virtual Machine Monitor.
Jailtime.org have Linux distributions that can run as Xen guests out of the box, obviating the need to create your own custom filesystems. The filesystems on this site have already been tweaked to deal with Xen’s idiosyncracies, and are also designed to be lightweight and minimally divergent from the original distribution.
It seems there are some issues with xen hwclock and centos and ubuntu xen vms !
You may find that installing
# yum install system-config-date
and using timeconfig instead might help