I have just been searching on the web for the exact same information. As far as I can tell they don't even tell you what STATE the centres are in before you submit!!!

It's frustrating because I'd like to know how long it will take, how far I'd need to travel, whether I should start asking my friends in NYC to house me for a day or two while I get my fingerprints scanned.

I'm hoping that there will be a biometric "application support centre" in Boston. I found a mention on British expat website that said they went to St. Paul, MN. If they have it there, they MUST have it in most major cities.

Sorry I can't be more helpful. It seems like they are being purposely vague.

-Megan