Found what looks like another useful blog at vmblog.com. More reading! Set up by David Marshall of “Virtualisation for Dummies” fame I referred to before. Should be a good site.
Slow progress on my efforts to compile Xen as am bogged down in a sea of dependencies.
On the vSphere side I have two VMs up and running: a Debian and an OpenSolaris. Both very easy to install.