I recently downloaded the latest beta for RHEL 5 and had a chance to test it out a little. Redhat is moving away from registration keys and is now using "installation numbers" which resemble MS Activation keys. These installation numbers are designed to tie a specific server/installation to a specific Redhat channel to provide a specific set of packages. I can see this as a way to control incoming revenue for Redhat and charge different prices for different channels in much the same way they are doing it now with the AS vs. ES channels.
I was able to test virtualization support included with RHEL 5 which includes Xen 3. The management interface makes it very easy to provision a new virtual machine and monitor resource usage on a host. The one disappointment that I had was that I was not able to use the xm command to get a console to the virtual machine after startup. I could list the running virtual machine and it showed it as "blocked", but it was actually waiting for a graphical login. For some reason there weren't any ttys available for login. I don't have a lot of experience with Xen so I'll have to find a way around this issue.
Anyone out there now the answer to this?