The Object Management Group's standard for object-oriented components. Microsoft's standard for object-oriented components. A standard for object-oriented access to XML and HTML documents. A specification for accessing XML documents using an event-based model. See the Resources section for links to sites that will assist you in locating tools for use with Python.
All software discussed here is open source.
XML is a very popular data format for Web service purposes. Its high structure and extensibility, broad support, and variety of related standards make it popular for encoding requests, responses, and communications between sub-components of the service. We have already touched on Python's built-in XML facilities. There are also many third-party XML tools. There is also Sean McGrath's Pyxie for an original approach to XML processing.