Well done! You have found our BETA name change, courtesy of Mojang AB 5000 minecraft Premium account holders will have the option to change their name. Mojang AB created a "Widget" to add to your site, therefore making the users of the site eligible for this exclusive offer!
All you have to do is sign in your current username and password then the you enter your email and password associated with the account when you have done that enter you're requested username. You will then receive an e-mail within 48 hours to notify you if you were part of the lucky 5000 BETA testers: