I think they've been at work transcribing their vast handwritten collection, which includes not only sermons, but scientific and philosophic writings, as well as some letters, for about 50 years!
Yale University press is publishing an anthology of his sermons. The first volume [url=http://www.amazon.com/Sermons-Jonathan-Edwards-Reader/dp/0300077688/sr=1-1/qid=1169044933/ref=pd_bbs_sr_1/002-5415958-1454438?ie=UTF8&s=books]The Sermons of Jonathan Edwards[/url] contains 5 previously unpublished sermons.
Among these is a very interesting adress to native Americans called To the Mohawks at the Treaty, which was a panororamic Gospel rendering of the creation, fall and redemption of man, with chronological and theological order (eventually leading up to a confession of the 'white man's' neglect of Christian duty to the Indian.) The sermon ends with a strong invitation to be "made fit for heaven." Delivered at a settlement in Stockbridge Massachusetts in 1751, Edwards appeared to distance his message from that of British representatives who must have been standing nearby. He began:
These honorable gentlemen treat in the name of King George but I in the name of Jesus Christ...
MC