Which Linux distro you use for PI/PCL development is up to you; there should be no problems with Ubuntu provided you use an up-to-date version.
Personally, I don't like Ubuntu, but this is just a matter of personal taste. I think Fedora 13 should work fine as a guest under VMware Workstation 7.1. I use VMware WS 7 extensively on Fedora 13 hosts and it works like a charm. Fedora 12 is officially supported as a VMware guest and it will provide you a perfect PCL development environment.
All that said, I really don't like Linux too much once I've taken the plunge for FreeBSD. BSD rocks!
