Noticing that you're approved will be pretty obvious. A goddess will post in your thread to welcome you, your "Unapproved" tag will change into a "Lord" tag, and most obvious of all, a lot of new boards will open up, pushing all currently visible boards to the left in a single column, while two more columns appear next to it.
You'll also notice a few more options, such as the ability to watch profiles and change your own profile, sending and receiving of PM's, being able to edit your own posts, etc...