This topic is containted in Chapter 13 of the book I participated on (Pro WCF: Practical Microsoft SOA Implementation). I did the first draft of Chapter 13 and spent quite a bit of time looking at the competing WS-* stacks.
If you're looking at interopability with WCF and the Java world this one is definately the most mature and more "meta-data" driven if you like designers, etc.
There's alot more on the subject in the book than what's on this blog posting referenced below. Along with some working examples and some "wire-level" inspection of what's actually going on using one of my favorite tools Ethereal (http://www.ethereal.com/) - which has become Wireshark http://www.wireshark.org/.
Link to The ServerSide Interoperability Blog » Tango in Web services: Java and .NET 3.0 interoperability