National Jukebox - Historical Recordings 1901 - 1925 maintained by the Library of Congress.
Cylinder Preservation and Digitization Project - A collection of historical music available for streaming and download from the University of California, Santa Barbara.
The Monterey Jazz Festival Collection - "The festival's archive - preserved by the Stanford University Archive of Recorded Sound - contains recordings of live festival performances throughout the history of this enduring American cultural institution."
Archival Sound Recordings - Digital access to selected recordings from the British Library Sound Archive. Researchers can search all recordings on the site, listen to recordings where copyright permits.
Internet Archive Music and Arts Collection - "The audio Music collection features nearly 600 virtual record labels found in the Netlabels collection, the unique contemporary compositions and performances found in the Other Minds collection, and the hundreds of popular songs from the early 20th Century found in the 78 RPM collection."
Early Music America - "Early Music America (EMA) is the not-for-profit service organization for the field of early music in North America." Click the Listen Now tab to listen to samples of music by early music specialists and performers.
Classical Connect - Free classical music site
Links to Early Music Recordings, in a list maintained by librarians at Yale University Libraries
NPR Music - National Public Radio interviews, profiles, videos, tiny desk concerts, and other performances.