Required items
1:  USB2 16Gig or greater USB drive, 32Gig recommended. 
USB3 will work as USB2
              USB3 requires drivers to be used, therfore it will behave as a USB2.
              FYI - look at the USB connector, USB2 = White  : USB3 = Blue
         Formatted as NTFS (External HD okay, SSD even better)
         Installation is 9Gig baseline
2:  Windows8 installation DVD or ISO as Virtual (you do NOT need to install to PC or Virtual PC)
        I'm running the Windows 8 Customer Preview (from here )
        in VirtualBox on a Windows 7 machine

                              (32bit 2.5G !! ) Product Key DNJXJ-7XBW8-2378T-X22TX-BKG7J
                                        or NF32V-Q9P3W-7DR7Y-JGWRW-JFCK8
                              which will probably expire when Win8 launches

3:  Download "Install-WindowsImage" PowerShell Script
         if link is broken, use this script, and documentation (Who the heck reads instructions?!?!)

Meat & Potatoes:
        Open PowerShell by typing it on the Start Menu, enure to right click and run as Administrator
                (Verify that your PC user ID is NOT part of the prompt!)
          if you find that you don't have the privilege of running the following commands
          you may need to elevate your privileges by issuing this command within PowerShell
set-ExecutionPolicy Unrestricted
4: Have the Win8 DVD mounted (I use a virtual drive) and take note of the drive letter (Mine is G:)
        and take note of the USB drive (Mine is H:)

5: Run the Install-WindowsImage script in the PowerShell window.
       Powershell command line uses the same directory commands as dos (CD, DIR,...)
       Change to the directory holding the "Install-WindowsImage.ps1" script you downloaded.

   Check how many configurations there are in the DVD Installer
.\Install-WindowsImage.ps1 -WIM G:\sources\install.wim
          (yes you need the dot slash in the front)
          (no you don't need to specify the ps1 extension)
         (and if you just type the name of the script WIM will ask for the parameter
              which you must enter   (win8 drive):\sources\install.wim   with the extension)

      If you have the Win8 Consumer Preview you will only see 1 option

         INDEX      IMAGE NAME
         [1]             Windows 8 Consumer Preview

  Perform the actual installation
.\Install-WindowsImage.ps1 -WIM G:\sources\install.wim -Apply -Index 1 -Destination H:

(Select the above text and copy/paste - change the drive letters)

Takes a few minutes, after several attempts I find that the longer it takes to install
   the longer it will take to boot & run.

While still in Powershell issue this command for bootfile creation. (Note the USB drive letter)
bcdboot.exe H:\Windows /s H:
Write down the Product key before rebooting

The first boot on any machine will be the longest

Want to make a USB Bootable Win8 installation ?
Use the ultimate in Windows formating at
         (Still need the Win8 DVD, but uber easy)