A couple of months ago Apple changed their policy regarding virtual instances of Mac OS X Server. The license agreement of Leopard Server now contains a part which allows you to install one virtual copy of OS X Server on a single Apple-labeled computer. More info about this change here.
Yesterday Pete Kazanjy of the VMware Fusion team posted an article about this on VMTN.
In this article they announced that after Parallels also VMware Fusion is capable of running a virtual instance of Mac OS X Server (Leopard that is) on Apple hardware. This was achieved without any modifications to Mac OS X kernel. They demo this Technology Preview on Macworld, which is currently on show in San Francisco (15-18 january 2008).
They have made some photo’s and screenshots while installing/running it, so take look: