On the About page of my silverlight 3 app I wanted to display the version number of the silverlight assembly (not of the web application).
In the Silverlight forums I found a simple solution by PBROMBERG:
Assuming that the xaml page contains a textblock txtVersion with no text.
Assembly asm = Assembly.GetExecutingAssembly();
string parts = asm.FullName.Split(',');
txtVersion.Text = parts;
the resulting version info will be displayed like: