The SOAP 1.2 specification was released as a recommendation by the W3C on 24-June-2003.

SOAP provides the low-level infrastructure for Web services. I have worked extensively with Apache SOAP, including interoperability with other SOAP implementations. The following are links to some techincal tips I have developed along the way.

Installing Apache SOAP
Basic Apache SOAP Coding
Apache SOAP And JBoss
Apache SOAP And CORBA
Visual Basic 6 Client for Apache SOAP Using the Low Level API
Visual Basic 6 Client for Apache SOAP Using the High Level API
Visual Basic .NET Client for Apache SOAP
Servlet Client for Apache SOAP
Apache SOAP Processing

I have worked quite a bit with NuSOAP, again including interoperability with other SOAP implementations. Because there does not seem to be any good tutorial on NuSOAP, I have prepared the following.

Introduction to NuSOAP
Programming with NuSOAP
Programming with NuSOAP Part 2
Programming with NuSOAP Using WSDL