With Digital Map Products (DMP), developers can now easily overlay over 100 million US parcels to more easily identify boundaries between properties. Using a simple, native method in Bing Maps and DMP's ParcelStream API with just 7 lines of code you can tap into this wonderful trove of parcel information. So, how is it done? Luckily, DMP even provides code samples and working applications that you can just copy, paste and run. The sample uses both Bing Maps Platform APIs (AJAX) and DMP's ParcelStream API.
The code in the walkthrough requires registration associated with your domain, so if it doesn't run for you it's because you need to get your own key.
More Info: Sample code & Walkthrough