Movie Ratings for Kids

Julie and I want to see a movie today, probably Shaun of the Dead, so we are looking for a movie for the boys to see at about the same time, at the same theater. I always end up going back to Google to find sites that review the content of films (particularly PG and PG-13 films) for age-appropriateness. Here are a few decent sites out there that I've checked out:

• Kids-in-Mind - Probably the most thorough out there, as it provides a great amount of narrative detail in addition to scoring the films on various dimensions (Sex & Nudity, Violence & Gore, Profanity).
• Grading the Movies - Uses a letter-grade scoring system on various dimensions (Overall, Violence, Sexual Content, Language, Drugs/Alcohol). This site gives a combination movie review and rating, dealing with a more subjective assessment than Kids-in-Mind.
• FamilyStyle - Hardly worth mentioning, this site scores films on various dimensions (Profanity, Nudity, Sex, Violence, Drugs/Alcohol) but provides very little commentary to back up the ratings.

We are contemplating whether or not the kids can see Mr. 3000 on their own. Looks like there may be too much profanity and sexual content for our liking, so we may just opt out of Shaun of the Dead and see Hero together as a family.