virtual OS solutions?

[Kevin Kempter]

Hi List;

I've installed Kubuntu 7.04 and I have needs to also have access to a Redhat 
based distro for working with RPM's & building custom RPM's for my clients.

I wonder which of the virtualization options bmight be the best in terms of :
a) ease of install
b) ability to copy/backup the VM
c) ease of administration 

I've tried vmware and it's ok but my machine runs hot as hell when I'm running 
a guest OS.

Anyone have experience with Xen, Virtual Box, other options?
Any advice, tips, etc? Any how-to's that would help me to install a Fedora or 
CentOS guest on a kubuntu host ?

Thanks in advance...