I recently bought a shiny new home desktop machine ( 6 GB RAM, 1 TB Hard Drive) to act like a server at my house.  I installed W2k8 R2 Enterprise, added Hyper-V role.  My goal was to be able to create VM’s for testing ‘stuff’.  I wanted to create one base image, sysprep and make copies when I wanted more machines quickly.  I’ve used VPC 2007 to create one image and copy / paste the VMC and VHD files.  Hyper-V is not quite that simple (yet).  Here are the steps I used.

• 
  
  Install w2k8 r2 on the host machine


• 
  
  Add Hyper V role


• 
  
  Create a new VM to act as the base IMAGE


• 
  
  Mount an ISO version of your favorite OS (windows 2008 or R2)


• 
  
  Load the OS


• 
  
  Run Sysprep (/generalize switch enabled), Shutdown


• 
  
  Inside Hyper V manager, Export to a alternate location


• 
  
  After Export is done, copy the entire folder to your permanent location


• 
  
  Inside Hyper V manager, import the VM you copied.


• 
  
  Rename to a friendly name.


• 
  
  Fire the new VM up, run through the sysprep process and poof!


• 
  
  Make sure you chose “Copy the virtual machine (create a new unique ID)’ option, this is not the default.

Another tip / trick I did on my base image (first VM) I created was after I was done, I renamed the image in Hyper V manager, because when you import, the name is retained when exporting.  This helps preventing the same name VM listed in Hyper V manager. 

Here is a good article that helped me figure out using export option.

http://www.virtualizationadmin.com/articles-tutorials/general-virtualization-articles/cloning-hyper-v-virtual-machines-right-way-part4.html