How to run Mac OS X within Windows Virtual PC?
Can a PC running Windows 7 with VMware, run Snow Leopard in a VMware virtual machine? Has it been done before?
As this is currently not allowed by Apple's Terms of Service, it is not officially supported by VMware and others. You can run OS X Server, but also only on original Apple Hardware.
There was an open Source Project once (PearPC, for emulating PowerPC on Intel) but I think that is dead now.