Most of these sources are freely available on the Web, with some use restrictions, and can be downloaded with software such as Adobe.
American Memory Project “Performing Arts, Music” contains a variety of links to digitized scores and sound files relating to American music.
American Viola Project Electronic scores for viola music by American composers.
Art Song Central Public domain sheet music for singers and voice teachers.
Bicinium: List of Duo Scores Sixteenth- and seventeenth-century scores for two instruments available in .pdf format.
Choral Public Domain Library One of the world’s largest free sheet music sites with over 8,000 scores.
Corsair: The Pierpont Morgan Library Digitized scores from one of the world’s best music manuscript collections.
Daniels' Ochestral Music Online Daniels' Orchestral Music Online is a unique orchestral music finder tool and an invaluable resource for orchestral librarians, libraries, planners, musicologists, conductors, and artistic directors.
International Music Score Library Project (IMSLP) Portal Page “The IMSLP is a project for the creation of a virtual library of public domain music scores, based on the wiki principle. Since its launch on February 16, 2006, more than 22,000 scores, for 12,000 works, by over 1,200 composers have been uploaded, making it one of the largest public domain music score collections on the web. The project uses MediaWiki software to provide contributors with a familiar interface.”
Mutopia Project A variety of classical music, with .pdf and MIDI files. 911 pieces of music are now available.
O’Neill’s Music Of Ireland Celtic sheet music; over 1850 tunes.
Sheet Music Consortium Sheet music collections from several libraries including UCLA, Duke, Indiana, and Johns Hopkins.
Variations A test project of scores digitized for the William and Gayle Cook Music Library at Indiana University.
WIMA: Werner Icking Music Archive Free sheet music files from the RAMA (Royal Academy of Music, Aarhus) Music Archives in Denmark.