The way to get the public key token using the .NET 2.0 provided utilities is to open a Visual Studio 2005 command prompt and typing: sn.exe -T [full path to strong named assembly]
However, there's an even easier way using the external tools dialog in Visual Studio 2005

  1. In Visual Studio 2005, click Tools -> External Tools...
  2. Click Add and enter the following into the different fields as displayed in the following screen shot:  
    •  Title: Get Public Key 
    • Command: C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\Bin\sn.exe  
    • Arguments: -Tp "$(TargetPath)" 
    • Uncheck all options, except Use Output window\
Now, you have a new entry listed in the Tools menu titled Get Public Key as shown in the following screenshot:




Assuming you have a project open that has been configured to be signed when built, and you've built it at least one time, selecting the new Get Public Key menu item from the Tools window to get the public key token and blob in the Output window, as shown here:





 Very slick! You can even take this one step further by adding a button to a toolbar by customizing your toolbar and adding a button from the Tools category. you should pick External Command # where # is the index of the external command from the External Tools window (in my screen shots above, this is External Command 3). Then you can change the name of the button to be Get Public Key as shown below:


Very cool!


Help From : http://www.andrewconnell.com/blog/archive/2006/09/15/4587.aspx