I attended one of the Library of Congress Institutes this past summer and had the pleasure of evaluating with the software techies their latest project.  Well, it is now released:

http://www.loc.gov/teachers/student-discovery-sets/

Check it out.  The new Library of Congress Student Discovery Sets bring together historical artifacts and one-of-a-kind documents on a wide range of topics, from history to science to literature. Interactive tools let students zoom in, draw to highlight details, and conduct open-ended primary source analysis. Full teaching resources are available for each set.