P2V

Does anyone know of a method of converting a physical server into a vertual server, something that has been tried and tested.

I have a quad core processor, HP ProLiant ML350 G5. The OS installed is Server 2003 SBS, which only uses a maximum of two processors.

I want to virtualized the physical server to be able to better utilize the processors.

Does anyone know of a good, working method of virtualization.