The Great78 project has released 25,000+ digital copies of early 78rpm records and are continuing their work on digitizing more of estimated 3 million "sides" that play for about 3 minutes. A gateway to the history of the project and where to download from is here: http://great78.archive.org
Read more:
http://www.atlasobscura.com/articles/internet-archive-78-records-phonograph
http://www.newsworks.org/index.php/arts-culture/item/106319-philly-company-digitizes-collection-of-25000-old-records-and-growing-free-to-download