Kodansha Encyclopedia of Japan
Continuously updated resource on all aspects of Japan.
Put the title of your story into the Search Window and you may get some background information.

General Folklore Sites

The Hero's Journey
Explore Classical Myth Structure

Myths and Myth-Makers
Full text of John Fiske's book Myths and Myth-makers, published in 1872

Japanese Folklore Sites

FYI: Folktales on the Japanese Internet

Ainu Folktales

Folktales from Japan

Ghosts, Demons and Spirits in Japanese Lore  

Tales of Wonder

Sites in Japanese

岡山の民話

Identifies the place of origin of certain Japanese folktales. 
Sometimes the alternate titles the stories have had throughout the years are given.
    

復刻版「紀州 民話 no 旅
Furusato no Minwa
Sites that identify the place of origin (in Japan) of certain folktales.  

   
Folktales from Umeda-machi, Kiryu-shi, Gumma-ken
This site lists the locations where the tales were picked up by city block.

Folklore in Yamagata    

Folktales from Sasayama, Hyogo-ken
Some have a little explanation with them. 

Storytelling Sites

History of Kamishibai

Learning Storytelling

The Story Connection

Teacher's Guide to Kamishibai

Tell a Story