You have to sign up for the Stratus Service, then you'll get a secret key. Use this key to build your URL with "rtmfp://stratus.adobe.com/" + secretKey. From then on you can go for whatever you like there.
i have followed the example using php and mysql instead of the python cgi, from here
but do i still need a web service url and if so what is it?
I believe that a web service URL is the URL that you should be getting data from. E.g. you will need to place a file relevant to the program you are running, most probably storing the list of users in your Cirrus application. Hope this helps slightly, i'm a bit confused too.