It seems you want to begin with Linux as a Windows guy. Why not to intall Microsoft Virtual PC? I bet it does support Linux and all modern distributions will likely work.
I also recommend VirtualBox as a good starting point for you if you want to use Windows as a hypervisor.
If you want to use Linux as hypervisor, I recommend to stick with standard KVM. E.g. in RHEL (CentOS) or Fedora you can use it easily. Definitely read this document: Virtualization Getting Started Guide
http://docs.fedoraproject.org/en-US/Fedora/18/html/Virtualization_Getting_Started_Guide/index.html
As it explains everything to start with virutalization including very easy setup and installation on Fedora Linux. It also applies to Ubuntu, but the installation procedure will be different. But you will end up using the very same tools and software.