Payment Notification Hook?

[ETSol]

Hello again,
Following up from my previous question, I'm still trying to find information on how to utilize a hook in s2member during payment notification, and also to retrieve the wordpress userid and member level associated with the payment notification. I'm using paypal pro forms.

From trawling through the forum and the codex, I believe that the hook to use would be 'ws_plugin__s2member_after_paypal_notify', but I can't find much detail on how to get the userid or the members level associated?

Any help would be really appreciated - I'm more a designer than programmer, and although s2member is incredibly easy to use so far this would just make it perfect for me!

Thanks again!