Looks excellent. My colleague at work has put together a Moodle course for teaching the use of digital (online) primary sources and has a wiki page devoted to other resources.
I was intrigued by this site. If you take a moment and contrast it with a similar project by the National Archives of Canada at http://www.collectionscanada.gc.ca/website/index-e.html, you'll see that the U.S. example has lots of Flash, and pizazz. The Canadian example is solid, fairly linear, and a bit dull (but some say that's us Canadians). I guess what I've been wondering about is this: While the U.S. site is a way cooler place to just browse, which place makes it easier to get the content you're looking for? I've looked at both sites and thought the Canadian was the better one for finding information, but maybe that's my national pride getting in the way. I find the American version a little overwhelming, but could that reflect the fact I'm not fifteen anymore?