HTTP with Port 80 allows to share Port 80 with multiple web applications. If you want other TCP ports to be shared by multiple applications, there is not an easy way to achieve the same. Windows Communication Foundation (WCF) allows multiple application to share the same TCP port. I had written an article on the same as how WCF enable a TCP port to be shared by multiple applications
Please have a look on
Port sharing feature of WCF
Read the complete post at http://dotnetpathak.blogspot.com/2007/08/port-sharing-features-in-wcf.html