This is the wrong place to ask, but let me take a stab at it.
The goal of virtual server is to allow one piece of hardward to host
more than one server. By 'server' I mean a set of services that would
normally reside on one machine. Could be a database server, a web
server, but I'm sure you get the idea.
With Virtual Server, you could not only have more than one server on the
same machine, you could even have different operating systems running on
the same machine. Still have some Windows NT server apps running? Not
problem. Load Windows NT into Virtual Server and have at it. Want to
run a print server through Linux? It too can share the same hardware,
but in another instance of Virtual Server.
Actually, all of this can be done with Virtual PC too. The extra
functionality provided by Virtual Server is a dashboard that allows an
at-a-glance look into the status of all of the running servers.
Hopefully that will give you the idea.
Bruce Johnson [.NET MVP]
http://www.objectsharp.com/blogs/bruce