Thanks Mike. "The Windows(R) Image to Virtual Hard Disk (WIM2VHD) command-line tool allows you to create sysprepped VHD images from any Windows 7 installation source. VHDs created by WIM2VHD will boot directly to the Out Of Box Experience, ready for your first-use customizations. You can also automate the OOBE by supplying your own unattend.xml file, making the possibilities limitless.
Fresh squeezed, organically grown, free-range VHDs - just like Mom used to make - that work with Virtual PC, Virtual Server, Microsoft Hyper-V, and Windows 7's new Native VHD-Boot functionality! "