These sites contain free scores from public domain (copyright has expired, usually pre-1923) music. The quality of the scores may vary.
Petrucci Music Library (IMSLP) - Search engine of music in the public domain.
Mutopia Project - Public domain scores of classical music, with some contemporary works made freely available.
Choral Wiki: The Choral Public Domain Library - Scores and associated literature for public domain choral music.
ChoralNet - Professional networking site for the global online choral community.
Program Notes are designed to act as guide to an audience listening to live music. They will inform about the sequence of music played and may give some information about the music.
Alexander Street Press - Music Online - American Song - A history database that allows people to hear and feel the music from America's past.
Alexander Street Press - Music Online - Popular Music Library - Contains a wide range of popular music from around the world.
Alexander Street Press - Music Online - Contemporary World Music - Delivers the sounds of all regions from every continent.
Garland Encyclopedia of World Music Online - Browse Cultural Groups or try an advanced search.
Internet Archive - Massive archive of free media including Creative Commons and public domain music.
Free Music Archive - Collection of music of a wide variety of genres cleared for a variety of uses.
cMixter - Music and samples made available under a resharable Creative Commons license.