Microsoft still hasn't quite caught the command line religion bug yet. It still takes a lot of code to perform simple tasks outside of the Virtual Server management web page. In the case of PowerShell, you even have to compile to C# code to create a custom DLL to use (um, ouch!). Fortunately, this freeware utility written by Jin Mao can fill part of this void for a lot of us too lazy to write a lot of code to do simple things (like pause and unpause a virtual machine).

VSPlus for Microsoft Virtual Server 2005

If you use Microsoft Virtual Server, you may want to take a look at this utility and test it.