Unlike VPS in Linux enviornment, cost may be prohibitive for MS Windows.
Virtual Server 2005, Standard Edition
$499 U.S.
Supports up to 4 processors.
Virtual Server 2005, Enterprise Edition
$999 U.S.
Supports up to 32 processors.
To set up virtual machines on a server, each installed copy of the Windows Server operating system must be separately licensed. For example, if you are setting up four virtual machines on one server to run one instance of Windows Server 2003 and three instances of Windows NT 4.0 Server concurrently, you will need one Windows Server 2003 and three Windows NT 4.0 Server licenses.