The whole 'Ultra' thing has a bad name in Europe because a minority of them such as Roma fans behave badly. Ultras believe in supporting the team by non stop singing right through games, colourful card displays and waving flags around.
It would be very difficult to set an organisation up for that as it will take alot of time and money, but if enough people are interested it could be done. The nearest team with 'Ultras' around here is Accrington Stanley, other Bitish teams include Aberdeen, Crystal Palace, Middlesbrough to an extent and York City.
http://www.youtube.com/watch?v=0LNuGbE849g
Just seems like abit of harmless fun to me, they just travel to games together and theres plenty of drinking involved! it's just another form of supporters club.