Here are a few places for you to look which might be helpful:

Japanese Religious Music, has a clear & concise explanation of types and, I think it had a couple of links;

http://www.searchenginecolossus.com is a HUGE search engine with links to individual search engines in almost any country you can think of;

Japanese Folk Songs CD for 12.95 US;

and, heritage site on Shirakawa with a wav file of a trad. song with flute.

Another good search engine is www.metacrawler.com, as well as,

www.dogpile.com.

Hope this helps. I will post more as I come across them.

katlaughing