www.thebirthsurvey.com has data for some (not all.)
It's actually a law in NY that hospitals must disclose that data, I believe MA or one other New England state as well.
ICAN is another good source.
The birth survey gets much of the data by calling state department's of health, so if the birth survey doesn't already have it for your state, if you DO call to get it, definitely pass it on to them so they can share.
