See also composer links & instrument links which point to pages which frequently include sound as well.
At this point, there are many general classical music midi sites, some of which include EM. These cannot realistically be listed in their entirety.
There is also a great deal of overlap between pages which can best be described as containing scores, and which can best be described as containing sounds. I have tried not to duplicate the listings on the two pages.
To Scores, Sounds & Sources
To Early Music FAQTodd M. McComb