Changing your account information is easy. Here are the instructions for customers using the Control panel. If you have a dedicated server, or an account in this website (which is free), first log in to the control panel (Click here to log in).
Your registered name will be displayed on the right upper corner, click on that. Now you will have two selections one to log out and other saying Update account, click on update account and update the changes and click save.
NOTE: Your email cannot be changed, once its registered you cannot change the email.