mazzy1026: If you post a reply to a message you are automatically subscribed (not sure if you have to tick the "email notification" button though). That way, when you log in, you can simply click "user cp" at the top right of the page to see all the threads you are currently participating in.
If you want this to happen automatically, I think you need to go to your User CP, then to Edit Options, then look for the option that says "Use 'Email Notification' by default?" and select yes. Remember to save the changes you've made.
And welcome to PPRuNE, V2+30 Flaps Up!