[CentOS-virt] CentOS-5.4, KVM, QEMU, Virt-Manager and kvm-qemu-img

What is the correct combination of packages to configure and manage VMs via virt-manager undet CentOS-5.4? If I use qemu then while virt-manager works I obtain SELinux alerts with respect to the real-time clock. If instead of qemu I use kvm-qemu-img then virt-manager simply does not work. It starts but it does not find any form of qemu and the selection boxes are all greyed out.

Further, do I need tun/tap to host VMs that themselves support virtual ips? The module for tun I found as part of the base install. But I cannot locate the module for ethertap and yum does not tell me where it is found.

Lastly, why is qemu 4.5M but kvm-qemu-img is only 125K?

Regards,