You have not stated where the Python code needs to reside. On the server, you can use XML-RPC or SOAP. Flash either supports them natively or has libraries for those. Your web service servers can be written in Python. This is the perhaps the best approach.
On the client, Python can be installed as a client side scripting language within IE on Windows. There used to be an article floating around on that quite a while ago. Can be deployed as a COM server on the client too and scripted within the browser. But this is of course neither a desirable nor portable solution. -- http://mail.python.org/mailman/listinfo/python-list
