OOooooooohhhhhhhh, I was shaking into my popcorn watching this movie!
It's pretty scary stuff. Basically this is a true story which revolves around the courtcase of a priest who performed and exorcism on a young girl called Emily Rose, said to be possessed by 6 spririts. Unfortunately the girl died and he's charged with manslaughter. The story looks at both the religious side of things and the prosecutings medical finding where they say she was just mentally ill and events such as stopping her meds contributed to her death etc etc etc you get the picture.
It's like an updated Exorcist. Not sure how long it'll last in the cinemas before some local complains about the Catholic content, but if you want a bit of a scare it's freaky.
The horrid thing is it's a true story, if you watch the movie then do some digging into the case via the net, the actual events are far more horrific.
Er enjoy!