Tomorrow the 18th this event will start on the US servers, maybe it will begin on EU servers on the 19th. Only time will tell.
It involves daily tasks (quests) that's soloable, and you will get influence for them. If you do these tasks every day you will be able to play the new classes 1 week before everyone else, this is the Elite reward. The Basic reward is a trophy and Advanced reward is a cloak.
There will also be a new scenario during this live event, called "Reikland Factory".
Here is a grab bag that explains this event in detail:
http://herald.warhammeronline.com/warherald/NewsArticle.war?id=449
