The powershell snapin comes with SCVMM v2.
However, Powershell can be used to access WMI which is available at the Hyper-V level. However, the Powershell snapin will not be available at the Hyper-V level only the SCVMM level.
that is where the virtual machine manager snapin resides today with Virtual Server and SCVMM v1 (you have to install an SCVMM admin console to get it and talk to an SCVMM server)