From http://www.redhat.com
Managing your RHEL 5 virtualized environment:
libvirt: a programmable management library providing hypervisor independence.
virsh: a scriptable command shell.
Red Hat Network enhancements to manage guest entitlements.
virt-manager: a GUI for virtualization functions (create, start, stop, suspend, resume, monitor, etc.).
RHEL Advanced Platform's Conga , a management utility providing a web-based control of storage, applications, and servers in small and large multi-cluster environments.