Note 99: For an introduction to SOAP and WSDL support in Delphi you can refer to Mastering Delphi 7 or Mastering Delphi 2005. The latter edition includes also a comparison of SOAP and REST techniques for implementing web services.
Although I didn't write that in the note, I'm thinking of updating my "Web Services in Delphi" material and turn that into a separate book (although it is 3rd or 4th in my book projects pipeline, so it won't happen any time soon).
This blog post is part of my "113 Delphi 2007 Handbook Notes" blogging project, to promote my new Delphi book.