If you're interested in joining, you can head over to the league at http://undisputedonline.net/forums/index.php
We have dedicated staff and members who are more than willing to help you around the site and introduce you to the league and how it works. And not only is it a league for the game, it is also a Forum where just about anything you can think of is discussed. Music, pop culture, movies, TV, etc. If you can think of it, most likely it's already being discussed.
Also, the league has several players that served first hand as testers for the game. THQ personally flew out five of our players to play the game for three days with them, making sure to eliminate as many cheap tactics and exploits in the game. No other league or websites were privileged to do this.