Generally, I use Rotten Tomatoes to see a cross-section of critical attitude towards a film, and they give Watchmen a respectable, if not overwhelming 63% as of this writing. Admittedly pimping themselves for fanboy-crazed clicks, the folks at Cinematical also compiled a bunch of quick blurbs about what critics are saying about Watchmen. Strangely, they left out Roger Ebert's positive review.
I have my ticket for Sunday. Can't wait.