Here are some interesting videos which give ideas for Viking lifestyles, characteristics and appearances.
Vikings are used in awesome music genre mash-ups too! Check this band called "Amon Amarth", a brilliant example of taking Viking ideologies and firing them through heavy metal. (An idea for the Cartoons "theme tune" direction?)
Here is more documentry style video showing about Viking culture
This is a play on the Vikings by the Muppets, which shows how the Vikings can be turned into something more silly and amusing as opposed to their serious, violent truth.