Can a virtual PC find out the identity of its host?

Unless I am mistaken, outside of server-provided virtualization tools (like VMware's 'vmware tools'), you won't be able to determine even that the VM is a virtual machine.

Perhaps running through Hyper-V's admin consoles you could determine which machine it is running on. Outside of that, I know of no such way to determine what you're looking for.

Hah. Came in here to tell you I'd struck out, unless you were (for some reason) using Microsoft VM instead of VMWare.

Microsoft puts the name of the physical host in the registry of the virtual machine under:

HKLM\Software\Microsoft\Virtual Machine\Guest\Parameters\PhysicalHostName

Hope that helps.

Worst case scenario: Locate it based on it's network connection, just as you would for a rogue machine. I start by determining which switch port it's connected to and then look up where that cable terminates.