The free Debian Linux operating system has added the OpenVZ virtualization software to its “unstable,” or development, distribution, known as Sid.
That operating-system-level server virtualization software, developed by the OpenVZ Project, is built on Linux and creates isolated, secure virtual environments on a single physical server. These virtual servers ensure that applications do not conflict and can be rebooted independently.
I’m not sure what this will mean for Ubuntu. AFAIK having OpenVZ in debian makes it relatively easy to add it in Ubuntu. Having some kind of Xen support is a goal for Edgy.