Actually, there is a feature of phpBB that allows you to change your own username. We have it turned off, because we don't want everyone coming up with a "cooler" username each week, and changing it. If that were to happen, there would be mass confusion as to who everyone was (except for Tim, since "teh" gives away all of his posts)
So anyway, I can actually change a username, but your post count would start over. I also don't want to change usernames for the reasons mentioned above.
Sorry dude, I don't mean to sound like a jerk, but your stuck with it.
- Justin