Got a copy of Simon Guest's “Microsoft .NET and J2EE Interoperability Toolkit” the other day. Simon defintitely did an outstanding job on this book. You can approach it from either a java perspective having to interop with .NET or from a .NET developers persepective having to interop with J2EE.
In particular, I liked the addition of WSE and GLUE material & code samples under “advanced interoperabily” as most of the stuff I've seen regarding webservices interop is pretty simplistic. Real world solutions with Web Services need the the facilities provided by the WS-* spec's so it's great to see this taken into consideration. Other interesting items addressed are things like presentation tier interop, async interop (Websphere MQ, and Biztalk), a huge section on web services (with the advanced stuff at the end of the book in the last chapter), comparisons between java and .NET (so that either way you approach the book you will be able to relate it to something you already know), and .NET Remoting.
Very thorough, and well written...
Great job Simon!!