Discussion Groups

• The official (and invaluable) Apache "Soap Users" list is where you can listen to an get involved in variety of discussions about how to use Apache SOAP for Java. You can Subscribe or just View the Archives. A "Soap Developers" list also exists for the participating developers of Apache SOAP.
• Microsoft's official XML-SOAP Discussion Forum [microsoft.public.xml.soap] - choose Web Development, XML/XSL, SOAP, xml.soap - for discussions on the Microsoft SOAP Toolkit.
• The DevelopMentor SOAP discussion mailing list
• WSDL : a fairly active yahoo group that discusses any WSDL-related issue.

Software (download and install at your own risk)

• Sun Java
• Apache Tomcat ( Tomcat 3.2 documentation )
• Apache SOAP for Java (required libraries JavaMail, JAF and Xerces)
• Active Perl
• SOAP::Lite for Perl
• Microsoft SOAP Toolkit (Visual Basic code samples)
• Systinet WASP for C++
• Lucin SOAP Toolset for Windows
• IBM Alphaworks WSDL Toolkit
• Simon Fell's pocketSOAP

SOAP Service Catalogs

• XMethods

Reference Material

• SOAP 1.1
• SOAP Security Extensions : Digital Signature
• WSDL 1.1
• UDDI 2.0
• XML 1.0
• XML Namespaces

Selected Articles

• Understanding Web Services [Arthur Ryman, IBM]
• The Web services (r)evolution [Graham Glass, IBM]
• An introduction to WSDL for SOAP programmers [Uche Ogbuji, Fourthought Inc.]
• A Young Person's Guide to The Simple Object Access Protocol [Microsoft]
• Introduction to Developing with the .NET Framework [Microsoft]
• Oasis XML Cover Pages : Simple Object Access Protocol [Robin Cover] (with FAQ list)
• SOAP for Platform-Neutral Interoperability [Kent Brown]

SOAP and WebServices Knowledge Hubs

• CapeScience.com WebServices
• IBM DeveloperWorks WebServices Zone
• WebServices Resource Center
• Userland's Soap.Weblogs.Com
• WebServices.org

Tutorials

• The Web services (r)evolution - Part 2 [Graham Glass, IBM]
• Introduction to SOAP using Apache SOAP for Java 2.1 [Pablo Fraile Iglesias]

Miscellaneous

• Soaprpc.com's list of available books on SOAP