I don't believe that SOAP is especially popular in the Python world. Note that an XML-RPC library is included with Python, but a SOAP library is not. Most "web services" are likely done using REST.
http://code.google.com/p/python-rest-client/
but I'm sure there are many others. Django has one built in as well. But I often just do it manually without loading any helper libraries - all you need is HTTP!