Aaron Stebner gives us the solution in the link below on how to modify the finished dialog using javascript to allow us to launch our app in a postbuildevent.
I was curious the best way to add a launch application checkbox in my setup user interface (in VS2005). Aaron Stebner tells us how in this relatively simple to implement hack in his blog:
http://blogs.msdn.com/astebner/archive/2006/08/12/696833.aspx