Hyper-V Program Manager
A new beta of WinImage has been released with support for viewing and editing virtual hard disks from Virtual PC and Virtual Server. You can download a copy of the beta from here:
Personally - I am really happy to see this - as I have always liked using WinImage for my virtual floppy disks and now I can use this tool for virtual hard disks too. Using this beta you can:
Note that this is a beta release - so it is advisable to backup your .VHDs before playing around with it.