This site from the Library of Congress provides access to many different types of materials related to the American experience.
This excellent guide provided by the Society of American Archivists and written by Laura Schmidt provides a good overall understanding of archival practices. This guide is available to read online or you may download a PDF version of the guide using the link on the right of the screen.
This is the page for researchers at the Smithsonian. Click on the Collections link at the top of the page to see recently digitized materials and other popular collections. You can also search their collections here as well as their finding aids.
Acts and Resolves are the legislative decisions that created the normal schools in Massachusetts, among other decisions. You can search by year using the list provided or enter a search term in the box at the top of the page. Find Acts and Resolves from 1692 - 2010 here.
The American Antiquarian Society is located at 185 Salisbury Street, Worcester, MA. Their telephone number is (508) 755-5221.