I heard this on the radio this morning. The law goes into effect July 2010 and is only for restaurants with at least 20 chains.
Unfortunately, that won't affect me because the places I go are generally not chains. It might help when I go out with coworkers. It'll also force Red Robin here to comply (and they are always wriggly about their calorie counts). I do go to Chipotle but I have a good idea about the calories there when I go so that isn't a big deal. Overall, I think it is a good thing.