At Java One, Harold Carr and Arun Gupta were demoing a real life interoperability scenario
showing MS Excel client talking to Java web service endpoint. Slides and demo screen-casts
are available at Arun's blog

I will show how to implement such scenario at upcoming Jazoon conference.
It will take place in Zurich (Switzerland) in June (24-28).

Please look at http://jazoon.com/en/conference/presentations.html?topic=Java_and_.NET_interoperability for complete list of Java and .NET interoperability related presentations.

Looking forward to see you there :-)