Interoperability is the problem Web services tries to solve, but let's face it, somtimes it seems much harder than it should be. One organization that is worth checking out is the WS-I, which stands for Web Services Interoperability. Both IBM and Microsoft are members and have posted sample applications compliant with the 'Basic Profile' that you can download. Here's the URL:
http://www.ws-i.org/implementation.aspx
