In order to unlock these characters, simply log onto X-Box Live, and download the characters through "Download Content."
This prevents you from having to use the password each time you want them.
Plug a controller into port 4 and access the Credits from Options. Enter the Konami Code below quickly to unlock all the unlockable songs. You should hear a short jingle if you enter it correctly.
Go to the Dancers section in Options, plug a controller in port 4, then hold down X and Y for about five seconds. A jingle will be heard, and you can switch to the new characters. NOTE: You must do this every time you wish to switch to these characters.