Virtualization is nice! A good practice for servers, since it makes things more secure, scalable, replacable, and replicable. All this at the cost of little added complexity.
Read the guide at howtoforge
This guide is written during an install of a Supermicro machine with 2 dual-core opterons (64-bit), 2 identical disks (for RAID) and a load of memory. Why OpenVZ and not XEN or the recent KVM kernel module? Well, XEN is not very stable for 64-bit architectures (yet), and it comes with quite a bit of overhead (every VM runs its own kernel) due to its complexity. KVM is very simple but restricts you to run a kernel as one process, so the VM cannot benefit from multi core systems.