Question : Pro's and Con's of Virtual Machine

We have 36 server, WIn NT 4 svr, Win 2K and WIn 2003 svr ent and planning to implement AD on a Win 2003 svr ent.Our goul is to consolidate some server via VM. However, since I'm relatively to this concept, can someone give me there un-bias professional opinion on the pro's and con's of implementing VM?

Thx,      

Answer : Pro's and Con's of Virtual Machine

another cool thing about vm is that you can mirror these machines in the same time that it takes to cut and paste. duplicating machines and configurations becomes a snap, you can also create clusters very quickly using separate physical machines to maintain redundacy.  It is also a great way to move servers to secure locations. By having multiple offsite locations to host from, you can run these machines from anywhere or copy them to DVD if you like.