According to the official website, the movie of TV Anime Ao no Exorcist (青の祓魔師, Blue Exorcist) will be premiered on December 28, 2012 in Japan. The movie was announced late September last year, with an expectation to be available to fans before the end of 2012. We are more than happier to learn about this since the series is one of the best of the season. The trailer page on the official website indicates it is coming soon and we will post it in this post when available.
The director did mention he would love to work on the second season of the series when the original Manga was enough for Anime production. If you read the the Manga, you will notice that there are lots of difference between the TV Anime and the Manga, and we are going to expect the similar thing happen to the movie. And in fact, the official website does provide some outline and I will somehow translate it with my lousy Japanese: Before the festival once every 11 years, True Cross Academy has already in the mood of celebration. In order to defense the demons, Rin Okumura (奥村 燐) tries to stop the Phantom Train where he meets a demon in a form of young boy. As for the young demon, he is probably be the one with golden hair sitting on the head of Rin Okumura in the above illustration.
Source: Official Website