Calling a .NET Form Application from Internet Explorer & Other browsers via mime type

Question

Scenario: I need to send a user a web link, this link hits a web service which returns content with a custom mime type application/wpcval created by me. I have associated that mime type with a locally installed windows form application to handle the content. I have the web service ready to go - how do I create a windows form application that accepts the returned content stream from the browser (IE, etc) once started via a mime type association? Thanks, Brad