Does anyone know anything about it? A couple of songs were featured in Kill Bill, but that is the limit of my knowledge of the sound.

Here's the wiki http://en.wikipedia.org/wiki/Enka

Listen here
Livin just to keep from dyin
[img]http://imagegen.last.fm/TheDarkTen/recenttracks/imgooley.gif[/img]

I youtube'd it and found some stuff.
(this one for example sounds quite similar to the first ending in Blood+ http://youtube.com/watch?v=3rs0ITZRUmc&feature=related) but it's a bit more recent. Traditional enka I think is Hibari Misora (http://www.youtube.com/watch?v=Q-zS-_H0m24).
From what I know it's a traditional type of music, often with themes of loss and loneliness, sung only by women I guess.

I for one don't like it alot as it emphasizes on lyrics alot and I don't understand them but even though I'm not an expert, I think the voices are amazing.