Common Sense Media is not Christian, and not all that conservative, but does provide a good amount of information. However, it doesn’t seem to consistently note instances of God’s Name being taken in vain in its language advisory.
Dove comes a close second to Kids in Mind as far as detailed content summaries are concerned, and they offer it from a Christian perspective.
Kids in Mind – may not be Christian, but it gives the most detailed reviews available
PluggedIn Online and MovieGuide – two sites that provide lots of valuable information for parents, but which are sometimes a tad over-generous in what they recommend.