A New article posted on MSDN covering interop between .NET and WebSphere, over webservices.  This one provides sample code for both .NET and WebSphere . There are instructions for what you need to download and install on the WebSphere side (including Eclipse), as well as all the steps necessary in the WebSphere tools.  In addition, the article gives some good practical advice for designing interfaces for interoperability and extensibility, specifically, on using a contract-first approach for interop.  Check it out and let me know what you think!