Check out kids-in-mind.com (http://www.kids-in-mind.com). It provides parents and other adults with objective and complete information about a film's content so that they can decide, based on their own value system, whether they should watch a movie with or without their kids. It's like a food labeling system which tells you what a food item contains. It is a reliable, content-based alternative to the confusing MPAA (US) movie ratings.
You may also find http://parentpreviews.com/in-theaters of use. Family Movie Reviews, Movie Ratings & More .. links to Expert Studies, Articles and Reviewer Blogs. Only rates movies less than R ratings.