Most people still use Windows. A few use a Mac. Fewer still use Linux.

VMWare Fusion does not allow 10.5 OS X to be installed, OS X Server 10.5 can be virtualized.

http://www.vmware.com/support/fusion2/doc/releasenotes_fusion.html

http://asendure.wordpress.com/2006/10/01/osx86-how-to-install-mac-os-x-o... show how to get 10.4.6 installed.