Well, while searching for the Jigoku Shoujo's Lyrics on the site, I've noticed there's only one song: the Jigoku Shoujo oepning :-/ I really wanted the Jigoku Shoujo ending, also the Jigoku Shoujo Futakomori ending and opening which I love very very much.
Opening: Sakasama no Chou (The Inverted Butterfly) by SNoW
Ending: Karinui (Basting) by Mamiko Noto
Jigoku Shoujo Futakomori
Opening: NightmaRe by SNoW
Ending:Aizome (Indigo Dye) by Mamiko Noto
Note: The info such as the name of the opening and ending themes and the artists are writen from the official site. I did not write other names or misspelled a letter or something like this. I did check if I had written correctly every single word.