Just noticed this for free as a festive way to play your way through LBP.
To get the costume simply go onto the Playstation store on your PS3, find the Little big Planet under A-Z of games and there are many costumes to download.
To help spread a little holiday cheer all the LittleBigPlanet players out there, we are giving a new Santa Outfit on the PlayStation Store starting tomorrow! Now all you LBP fans out there can jingle your way through the holidays in style. The suit will be given away across two release waves over the next couple of weeks.