The Library of Congress has digitized its collection of Andrew Jackson’s papers. You can find a description of the collection’s organization at the link.
While the papers have been digitized, they have not been transcribed or annotated. Still, this project opens up enormous possibilities for those who study Jackson’s personal life and political career.
The LC staff is planning to digitize Martin Van Buren’s papers over the next two years, which I’m pretty ecstatic about, for obvious reasons.