I don't. I usually look at reviews from the New York Times, the New Yorker, and sometimes IMDB and/ or Rotten Tomatoes. Usually between them I get a pretty good idea of what the movie is like without too many spoilers.
I'm interested if you find a site though. We have the same problem. Mostly we don't care about bad words or sex (we just saw "Scott Pilgrim vs. the World" which was highly inappropriate in parts, but nothing too bad, and sozlet loved it). She's not real robust on the scared-sleepless front, though, we have to be careful about that. ("Scott Pilgrim" had a lot of violence but it was bloodless/ cartoony.)