The Library of Congress has been working on a great project called the National Jukebox, making historic sound recordings from their collection available for the first time digitally.
The Library of Congress presents the National Jukebox, which makes historical sound recordings available to the public free of charge. The Jukebox includes recordings from the extraordinary collections of the Library of Congress Packard Campus for Audio Visual Conservation and other contributing libraries and archives.
You can find out more about the project here .
This project often involves a painstaking process of analyzing various copies of the same 78rpm recording and finding just the right one for digitization.
Here is a slideshow example of the workflow process from beginning to end.