The mesmerizing song used in the trailer, full of high-pitched, wolf-like yelps worthy of Karen O, is a new track from Fever Ray, a Swedish band which is actually just the solo project of Karin Dreijer Andersson. You can check out her site here: http://feverray.com/
The track itself probably won't be released until the film itself comes out in March, but you can hear a preview of it towards the end of the trailer:
Maybe this movie won't be anything like the Twilight movies. And maybe it will follow the trend of having a surprisingly wonderful soundtrack. One can only hope.
~Ellie