Begun in December 1998, CPDL is one of the world's largest free sheet music sites.You can use CPDL to find scores, texts, translations, and information about composers.

A collaboration between the American Choral Directors Association and the Library of Congress. Contains public domain choral music that users can download, information on the composers, and material related to historical context and stylistic features.

CyberBass is a free service that provides online MIDI accompaniments to many standard choral works. In addition, separate MIDI files for each individual voice part are available as an aid to learning and practicing individual parts.