Roger McGuinn's folk corpus. I found these poking around Gutenberg today.
→[More:]I only downloaded one, since I'm on dialup at home today, but it's a decent version of John Henry. For some reason it wouldn't load in my iTunes (Os X.2.8, iTunes 4), but it played fine in VLC.
I went to Gutenberg for Melville etexts to go with the excellent (!) biography by Andrew Delbanco that I'm reading, but for some reason they don't have a copy of the ambigious one, Pierre. Boo. I'm off to the used bookstore.