There’s an entire web site dedicated to collecting links to movie reviews about all the current releases.

More to the point, they tally positive versus negative reviews so you can get an idea of the way the overall wind is blowing.

VERY rarely are all the reviews unanimous. The only movie I can think of to achieve that rare honor was “Toy Story 2”, for which they located 67 reviews all of which were positive. Quite an accomplishment.

http://www.rotten-tomatoes.com/

I visit the site regularly. By the way, the consensus about “Mission to Mars” is very strongly negative. They’re running 3:1 against on 60 reviews so far.

It’s a nice mix of pro-views and fan-views, too.