The open source Xen virtualisation suite has caused a bit of a stir within the Linux world because it combines the power of VMWare without the proprietary code and cost hassles. Unfortunately Xen is not the most user friendly thing in the world to setup or configure. For a large organisation this is not so much of a problem because they can afford to hire expensive consultants or train their in-house staff. For smaller players or individuals interested in the concept but unwilling to invest hours into training XenSource have released XenExpress.
XenExpress fits on a single CD and can be downloaded without charge from the XenSource website (they do however ask for a few contact details). To setup your very own Xen host you just boot the computer from the CD, answer a few configuration questions like time and network setup and then just sit back and watch as XenExpress turns your computer into a fully functional Xen platform (for further instructions checkout this howto). After installation is complete configuration of the Xen host occurs remotely via a Java desktop application that runs on Windows, Linux or after a little hacking OSX. Most of the basic Xen tasks like virtual instance management and system maintenance can be accomplished through the interface without much effort or reference to the user guide. If you are an advanced user you can also bring up a terminal on the Xen host and run your normal Linux commands as at its heart XenExpress appears to be a slimmed down Red Hat distribution.