Already own MDOP? Start using what you bought today by downloading Assset Inventory Service (AIS).
The easiest Software+Service product to use right now is the Asset Inventory Service (AIS) in the Microsoft Deskop Optimization Pack (MDOP video here).
In fact, a thorough step-by-step guide (http://technet.microsoft.com/en-us/library/bb964349.aspx) takes you through setting this up in your environment quickly, so you can start viewing reports right away without worrying about an infrastructure deployment.
The next milestone version of this online service (AIS 1.5) is coming soon, and people are already talking about what new features are expected: http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=2224230&SiteID=17