Howtoforge posted a guide about virtualization with XenServer 5.5.0
This Howto covers the installation of XenServer 5.5.0 and the creation of virtual machines with the XenCenter administrator console. XenServer is a free virtualization platform from Citrix, the company behind the well known Xen virtualization engine. XenServer makes it easy to create, run and manage Xen virtual machines with the XenCenter administrator console. The XenServer installation CD contains a full Linux distribution which is customized to run XenServer.Virtualization With XenServer 5.5.0