When one talented programmer succeeds in implementing something, you can be sure another is a step behind making improvements. Sam Ruby provides a stripped down version of Phillip’s Python wrapper for the Microsoft.com Web Service that doesn’t depend on a toolkit or XML parser and supports one operation: Top 10 Popular US Downloads.
Looking at the implementations these guys have done, it’s clear that the bulk of the work on non-.NET platforms is implementing WS-Security. It strikes me as a worthwhile challenge to try it out. I wonder how easy it is to get Apple’s SOAP libraries to support the headers required.
Other notes: Both a human-readable description of the web service and a WSDL description are available.