LiederNet Archive Word-for-word translations and texts for vocal pieces.
The Piano Education Page For pianists, teachers, and students. Articles, composer bios, over 600 MIDI files and practical information; also useful to music educators in general.
American Memories site from the Library of Congress and Performing Arts Encyclopedia from the Library of Congress Digitized collections relating to American music.
Free Music Scores International sheet music for 35 different instruments
19th Century American Sheet Music University of North Carolina at Chapel Hill
WLSCM Web Library of Seventeenth-Century Music
DIAMM Digital Image Archive of Medieval Music
Gallica Bibliotheque Nationale de France
University of North Texas Virtual Music Rare Book Room focus on 18th Century Opera
Music Treasures Consortium Library of Congress