I stole this paragraph from Calluna on another thread.
For anyone who hasn't figured it out yet and wants to know, if your name was automatically converted to lowercase when you signed up and you want capital letters, you can change your "display name" by clicking on "profile" in the menu near the top of the screen and then choosing to edit it. That's also where you can add avatars, signatures, etc., if you so choose.
So that's how you repair the capitalisation issues with your username. If you have any other concerns or questions about how to go about making you uniquely you, ask here and we'll do our best to muddle through with you. We ask for a little patience; this is new to us too. ;D