Hadn't thought of that possibility. It's good to learn something like this; this is an early foray for me into the subject of genealogy and demonstrates how complicated it is.
Is there a central directory of national archive addresses on the web, or is this the kind of thing found in a large urban library? I have a book with some contact info, but it's very out of date, published in 1990. How would you get city, state/province ones, aside from writing to the national sources?