Some schools have installed server virtualization and have achieved a certain level of comfort.  Server Virtualisation refers to the sharing of one physical server for two or more functional servers (for better utilisation of assets). We use the term comfort to denote that nothing has gone wrong presumably and we shy away from saying that server virtualization is a must for schools.  If we search the Internet on the use of virtualization in schools, we may find an article published by IBM- a leader of virtualization technology promoting electricity bill reduction as the benefit achieved by a school.  We may also find a few articles published by Microsoft on a range of benefits but Microsoft is not known as a server virtualisation technology leader.  We did not find articles from VMWare (also a technology leader) and presumably VMWare has focussed in the enterprise space and not schools. 

Desktop Virtualization is a different to Server Virtualisation.  Previously it is called Thin Client (now Zero Client appears) meaning that the desktop does not need a fat operating system such as Windows XP or Windows 7.  Instead the desktop has the minimum software for connecting to a server which will supply the full suite of operating system and applications to it.  Thin Client has been around for decades and is not new.  Thin clients depend substantially on the network and their parent servers more so than fat desktops.

In both situations, there may be a saving of hardware cost but there is definitely a higher software cost and higher demand on the expertise level of the Information System manager.  Think fitness for purpose and total cost of ownership.