Howtoforge posted a tutorial about setting up KVM on Ubuntu 12.04 LTS

This guide explains how you can install and use KVM for creating and running virtual machines on an Ubuntu 12.04 LTS server. I will show how to create image-based virtual machines and also virtual machines that use a logical volume (LVM). KVM is short for Kernel-based Virtual Machine and makes use of hardware virtualization, i.e., you need a CPU that supports hardware virtualization, e.g. Intel VT or AMD-V.

  Virtualization With KVM On Ubuntu 12.04 LTS