Newbie - I want to trigger an action when a user creates / updates a profile
You can use the Rules module for that.

http://drupal.org/project/rules

Create a new triggered rule and set it to fire on event "User account has been created" or "User account has been updated."  If you're using Content Profile, you'd set the event to be "after saving new content" or "after updating new content" and specify the node type was whatever you're using for content profiles.