In order to use this , you have to just add this to your page or even post in your Blog:
"http://silverlight.services.live.com/invoke/accountId/appName/iframe.html", where account ID is your account ID of Silverlight Streaming account details and appname is the name you have given to your uploaded Silverlight application.
Here's example which shows an animated Silverlight logo using the code given below, uploaded to Silverlight Streaming as an application of the account ID #32 and uploaded appname as SlLogo.
This is all you have to put to get what you are seeing at the bottom- an animated logo of Silverlight logo
Check out these Links referred for more details: