Microsoft released Windows 7 last year which has lots of functionalities including a nice UI. Among those features one of the most user friendly feature is Pin/Unpin application to Taskbar. You can develop WPF or Windows Forms applications in which you can implement this feature. But do you know that this is also possible in Silverlight? Yes, Silverlight 4 has the power to talk with any other application using the COM API. You can read one of my earlier article [Silverlight 4: Interoperability with Excel using the COM Object]. So, how can I develop such functionality in my Silverlight 4 application? Here I will describe you step-by-step to let you know about the feature. After reading this article you will be able to pin/unpin any Windows application to your Windows 7 taskbar directly from your Silverlight 4 out-of-browser application.