According to everything I have read, you have to have Win8 Pro or Enterprise in order to have the built-in HyperV client functionality.
If you don't want to upgrade to Pro, try VirtualBox (free) or VMware Workstation (not free).
Edit: never mind that last bit. MSDN login finally went through...
Edit2: well upon further inspection, it seems that there are mixed results getting the WP8 VM working under VirtualBox. Link & Link YMMV I guess.