Microsoft had earlier released Tafiti, a search front-end,which uses Silverlight and Live Search and gives a richer experience in search. Check more details here: Microsoft Tafiti - Silverlight based search front end
Today, Windows Live Platform team released the Tafiti Search Visualization source code to CodePlex, which means any developer can download, modify, and resell the code (see MS-PL License for all the details).
So get your hands on the source code and find out what's in the code that combines Silverlight and Windows Live Services. A very good move to provide the source code. You can also find earlier released more of such source codes in the CodePlex as QuickApps. Windows Live Quick Applications are a set of working applications developers can download and use as reference implementations or starter kits for the Windows Live Platform.
More details here: ANNOUNCEMENT: Tafiti Search Visualization Quick App
Angus Logan in his blog had already given a hint few days back, New Quick App coming in a couple of days but had not revealed what it was.