I have created an app and submitted it for review with Facebook to allow easy registration to our site. This should be in effect in a few days. If it does not work for you please wait a few days then try again. This will work for existing user accounts also. If you would like to have a certain username rather than a FB_ID username then create your account first. If you don’t cant then just register with your FB account by clicking the registration button.
Sorry it is blurry I am getting tired again and not thinking.