In my recent experimenting with Axis Web Services I found the following useful resources on Web Service interoperability between .NET and Java.
http://wiki.apache.org/ws/FrontPage/Axis/DotNetInterop
http://weblogs.asp.net/smguest/articles/TopTenWSITips.aspx
http://www-128.ibm.com/developerworks/webservices/library/ws-tip-j2eenet2.html
Update: Simon Guest has a serise of webcasts from the recent “interoperability month” conducted by MSDN, including two on .NET and Apache Axis 1.2. This one uses a .NET client and Axis service (at a high level this is similar to my recent discussion of Axis JWS, but Simon apparently discusses the more “fully featured” WSDD approach). I think I'll wait for broadband to be hooked up later this week before looking at them.