http://www.youtube.com/watch?v=pOqE2flRHyE&feature=related
it starts around 4:30

i think the bgm is a traditional children's song "to o rya n se" in Japan.
Japanese people has sung it for some hundred years.

http://www.youtube.com/watch?v=S0pp6JN8L1U&feature=related

"to o rya n se" in English can be "you dare go through".

the lyrics of it has some renderings through people, i can not tell you the correct one, sorry.
but because of them, it's often sung as horrible/mysterious/whammy song.

omg omg, thank you so much, its been bugging me since i first heard it ^-^

i'v just found an interesting video.
http://www.youtube.com/watch?v=j14c49PvxkY&feature=related

according to Wikipedia in Japanese,
there are some traffic lights that sounding the melody "to o rya n se".
but i think they must be rare.
at least i've never seen such the traffic lights in my life.

http://www.youtube.com/watch?v=pOqE2flRHyE&feature=related
in this video, i can catch a traffic light at 4:20.
maybe, the bgm is from the traffic light.

...sorry,my parents said to me that
' i have often heard the melody "to o rya n se" from traffic lights. '

what's this?

i don't remember that... oops! this must be a curse of "to o rya n se" to me!!