I see that the question you are really asking is how would you get started with Silverlight. Well, first of all you are going to need the Silverlight SDK and a version of Visual Studio you can write Silverlight applications in.
If you go to
this[
^] page, you can find the links you need to download the latest version of Silverlight and the SDK, as well as links to Visual Studio.
I would suggest that you read and watch the tutorials available on the Silverlight site to get a basic understanding. When you want to go further, there are numerous excellent tutorials here on Code Project.