HowTo map VHD on host PC?

I installed some app on VirtualXP. How I can access to VHD/folder from host computer?

You can either access the application through the XP Mode published apps (under the Windows Virtual PC folder in start menu).

If you have Win7 Pro or Ultimate, you can mount the drive as if it were a physical device. Use Disk Management to mount and unmount the VHD file.