Before I go into specifics I wonder if you'd share some further details about
the treatment you've had in the past and what type of headaches you have. I ask this because, while headache specialists and centers are great resources, they don't need to be, and in many cases ought not to be, your first choice for treatment. Aside from tit being a lot easier getting an appointment, many non-headache specialized neurologists are able to successfully treat common headache disorders. As you haven't posted anything about
your history I don't know if you've gone down this path yet--but if you haven't you should consider it. From the 10 years that I've had a headache and talked to many other sufferers and doctors it's my belief that the best way to seek treatment for headache problems is to first see your general practitioner. If you have a headache disorder that isn't simple to treat you'd next be sent to a neurologist and, then, if the neurologist can't nix the headaches then your proceed to a specialist or clinic (This is my opinion and experience. It might not be right for you and if you've already been down these avenues, by all means ignore this preceding section).
I live in Philadelphia but I have some experience with other headache centers. Personally I go to the Thomas Jefferson University Hospital Headache Center is Philadelphia and I've been going there for about
6 years. There are also several other good options in Philadelphia like the University of Pennsylvania and Drexel/Hahnemann University Hospital. If you were to go there you'd probably have to wait a couple of months for an appointment (less if you see one of the Nurse Practitioner who are very good). And make sure to avoid Dr. Silberstein (the Director of the clinic). He's actually the most difficult doctor there to get an appointment with but let's just say that's a good thing.
In Pennsylvania I would also recommend the Lehigh Hospital Neurology Center in the Lehigh Valley. I went there for an additional opinion several years ago and, while they weren't able to suggest anything new (this was after 6 or 7 years of treatment), they were well-informed, personable and easy to work with. If you can get an appoint with Dr. John Castaldo, I highly recommend him.
Other than that I have heard some good things about
the headache treatment center in Pittsburgh but I don't have any personal experience there.
You might want to look at the American Headache Society® (AHS) Committee for Headache Education
which has a handy tool for finding specialists.
Best wishes and post back if you have any further questions,