Today a resource for musicians: IMSLP, a repository of public domain scores that offers untold riches..
From their FAQ:
IMSLP stands for International Music Score Library Project and started on February 16, 2006. It is a project for the creation of a virtual library of public domain music scores based on the wiki principle; it is also more than that. Users can exchange musical ideas through the site, submit their own compositions, or listen to other people’s composition; this makes IMSLP an ever-growing musical community of music lovers for music lovers.
It takes a bit of trial and error to get the hang of searching it (and the instrumentation search can be quirky), but in addition to many, many scores, there are recordings, talk forums, and historical notes. Combined with “ForScore,” a sheet music app for the iPad, IMSLP has become a a regular browsing destination for me–fueling, among other things, an arguably unhealthy fascination with 19th century salon music. God was there a lot of it!
One such treat, the once wildly popular “Berceuse” from Benjamin Godard’s opera Jocelyn.”
A Few Reasonable Words 