Via Jorgen Thelin I came across WSFX, an Apache project to create open source WS-* implementations. It seems to be in its infancy, but there are already subprojects for WS-ReliableMessaging (Sandesha) and WS-Addressing. I strongly believe that support for asynchronous interactions is a critical factor to deliver on the Web service promise of Loose Coupling, and for wide-spread acceptance of any standard, having an open source implementation is great.