If you contact Dustysage or MonorailMan, they should be able to change your name, but you can only do it one time, so choose wisely.
I don't think regular mods can change your name, since Yoyo didn't say he could or offered when you asked on another thread a while back.
So you could just search Dustysage or MonorailMan on the members list and PM them about your request.
Yup... only the administrators (Dusty and Monorail) have the power to change a user name.
Just remember, they are both very busy with things not only here but in real life as well, so if you request a change it might take a bit of time to get it done.
And yes... pick wisely because its not something you can do on a whim everytime you get tired of your current user name. They really don't like to change it at all, but if you ask nice and explain... it could happen.