Apache Stonhenge, the project we helped start in the Apache Incubator to build a set of SOA apps to demonstrate interoperability, just did their first milestone release. Congratulations to the team!
Its quite a bit of work to get the first milestone out as the developers have to align the project with ASF requirements, learn the release process etc.. But its a great feeling when its all done!
Download it and give it a whirl .. you may be surprised at how interop is much more real now!