International Music Score Library Pro...
http://imslp.org/wiki/Main_Page
A virtual library containing all public domain music scores and/or sheet music, as well as scores from composers who are willing to share their music with the world without charge.
WBAI's Here of A Sunday Morning
http://www.hoasm.org/VIIF/Rameau.html
Interesting website maintained by the host of WBAI's early music program.