I've been doing a lot with virtualisation lately....

Firstly I run Parellels (http://www.parallels.com ) on my MacBook so that I can use Agendus (a great little app from http://www.iambic.com ) which syncs with my Palm T5.  I also run MYOB our accounting system from time to time as well... other than that, aside from testing the odd bit of windows software here and there and testing websites under Internet Explorer, I don't use it that much... but I can say that its brilliantly fast.  I'm running Windows 2000 SP4 and I allocate 256Mb of ram and its as fast as most Windows 2000 PCs I've used... people I show it to are amazed. I've also run Linux virtual machines as well.

Secondly, I use free Vmware Server (http://www.vmware.com ) for a whole range of stuff.  I have one client who is running numerous mission critical Windows and Linux servers on it and is grinning from ear to ear.

So whats the big deal... simple... bang for buck... if you have servers that spend most of their time doing not much... why have seperate hardware for them?  If you want to test something out without putting it on one of your key servers, just power up a virtual server... the possibilities are endless, not to mention all the disaster recovery benefits etc.  Of course VMware have their Virtual Centre 3 product as well which has some fiarly fancy features like being able to move a virtual machine from one host to another on the fly without users noticing .... but thats for bigger shops who canafford to go down the SAN path (mind you thats getting cheaper these days... maybe I'll talk about that next week).

Tip of the week: Parallels Destop for Mac -  (http://www.parallels.com ) - get the best of both worlds.