Silverlight Development Requirments

If you want to develop the Silverlight website, you will need the following softwares. Note that it would be the best if you try to install those softwares on Virtual Machine. If you don’t have the Virtual PC then you should read about things that you need to uninstall before installing and you should search the documentation in forum or Google.

• Visual Studio 2008 ( download )
  Microsoft Visual Studio 2008 provides an industry-leading developer experience for Windows Vista, the 2007 Microsoft Office system, and the Web. In addition, it continues in the Microsoft tradition of development language innovation
• Silverlight 1.1 Alpha September Refresh (download)
  Silverlight 1.1 Alpha is intended for developers and designers interested in learning more about how to build experiences with Silverlight using both managed code and Microsoft JScript.
• Microsoft® Silverlight™ 1.1 Alpha Software Development Kit (SDK) (download)
  The Microsoft® Silverlight™ 1.1 Alpha Software Development Kit contains documentation, samples and tools for developing Silverlight applications.
• Microsoft Silverlight 1.1 Tools Alpha for Visual Studio 2008 (download)
  Add-on for Visual Studio 2008 for developing applications for Silverlight 1.1 Alpha
• Microsoft Expression Blend 2 December (download)
  The Expression Blend 2 December Preview lets you create Windows Presentation Foundation (WPF) applications as well as Microsoft Silverlight™-based applications. Additionally, you can export content from Microsoft Expression® Design in a format that you can use in Silverlight-based applications created in the Expression Blend 2 December Preview.

For further detail you can go to below link:
Silverlight GetStarted