HowtoForge posted a useful 3-parts guide on how to install and use Xen-Tools on a Debian system where Xen 3.0.3 is installed:
This guide describes how to install and use xen-tools, xen-shell, and Argo on a Debian system. All three packages provide useful tools for the administration of virtual Xen machines.
Xen-tools is a collection of Perl scripts that allow you to easily create, update, and delete Xen guest domains.
The xen-shell provides a command-line interface to owners of Xen domains so that they can manage their Xen domains without the help of the server administrator.
And with Argo, you can control Xen domains through a web interface or through a menu on the command line. All three packages were developed for Debian systems, but might work on other distributions as well….
Read the whole guide at source.