MSDN Code Gallery just released a first version for a very promising tool: WIM2VHD. With this you can take a raw WIM file (like the ones included inside any Windows 7 or Windows 2008 R2) or a custom WIM (like a captured and customized image) and converted directly to a VHD that you can boot directly using Virtual PC, Virtual Server or Hyper-V.

Take a look at this link: Windows(R) Image to Virtual Hard Disk (WIM2VHD) Converter

Introduction

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!

Requirements

• A computer running one of the following Windows operating systems:
  – Windows 7
  – Windows Server 2008 R2
  – Windows Server 2008 with Hyper-V RTM enabled (x64 only)
• The Windows 7 Beta Automated Installation Kit (AIK) or Windows OEM Pre-Installation Kit (OPK) installed.
• A Windows 7 or Windows Server 2008 R2 installation source, or another Windows image captured to a .WIM file.

How to Use It

Create a Windows Server 2008 R2 Server Standard Core VHD, named foo.vhd
CSCRIPT WIM2VHD.WSF /WIM:X:sourcesinstall.wim /SKU:SERVERSTANDARDCORE /VHD:C:foo.vhd

Create a Windows Server 2008 R2 Server Standard VHD with an automatically generated name
CSCRIPT WIM2VHD.WSF /WIM:X:sourcesinstall.wim /SKU:SERVERSTANDARD

Create a Windows 7 Home Premium VHD with an automated setup answer file
CSCRIPT WIM2VHD.WSF /WIM:X:sourcesinstall.wim /SKU:HOMEPREMIUM /UNATTEND:C:stuffunattend.xml

Apply the first image in a custom WIM to a VHD named custom.vhd
CSCRIPT WIM2VHD.WSF /WIM:C:stuffcustom.wim /SKU:1 /VHD:C:custom.vhd

Cheers!