I just saw this question being asked, so thought I would should with everyone:

Question: “If I have a paid subscription to Windows Intune, do I need an existing Operating System to install the Windows 7 Enterprise license included with the subscription?”

Answer: Yes – from the FAQ:

What are the Windows 7 Enterprise upgrade rights included with Windows Intune?

All of your managed PCs covered by Windows Intune may be upgraded to Windows 7 Enterprise as long as the qualifying OS is one of the following business editions of Windows: Business, Professional, Ultimate, or Enterprise.

The machines must also meet the Windows 7 system requirements. This list can be found at http://windows.microsoft.com/systemrequirements.

In addition to Windows 7 upgrade rights, Windows Intune customers will also have rights to upgrade to future versions of Windows, as well as downgrade rights to older versions. As long as your subscription is active, you will have access to the best version of Windows for your business to standardize on, making your PC environment easier to manage.

The operating system does not have to be Windows 7, but you do need a qualifying OS (XP Professional, Vista Business, Enterprise or Ultimate or Windows 7 Professional, Enterprise or Ultimate)

ttfn

David