So I did a demo a few weeks ago on a simple solution that uses the current BizTalk Services deployment. You can find it here:

http://cid-2acaee0f398245b2.skydrive.live.com/self.aspx/BizTalk%20Services%20Samples/SecretMission.zip

Now, the idea behind the solution is that there is a single server running behind a firewall, and that there are many instances of a client application that will be connecting into that server from the Internet.

Using the Relay and Identity services in BizTalk Services, I simply authenticate and authorize each client logging in, then connect them to the server through the relay where they can get their “secret”.

This is a classic integration scenario where organizations that want to connect client applications to their servers securely behind the firewall, can do so using an Internet based middleware platform.

Make sure before you run this that you sign-up and setup your BizTalk Services account, as you’ll need to enter your account name in the code to connect to the Relay.

Happy trails :)