Found a great new trick today for mounting Virtual PC VHD files as drives within the host operating system. In the Virtual Server 2005 R2 SP1 installer is a utility called "VHDMount". If you install Virtual Server you can elect to only install this utility (if you do a custom install). This will create a directory "[drive]:Program FilesMicrosoft Virtual ServerVHDMount" within it is a file called VHDMount.exe. This is a command-line utility that you can use to mount your VHD files. I regularly use a VHD drive that I share with multiple VPC's that has common development utilities, and being able to populate that drive without having to boot up one of the VPC's as a big plus.