I remember there was a lunachicks song called 'I don't care' one of the lines in the song was "I farted on the train..I don't care"
Also there is a song/video called 'who farted" and it ends with this girls singing about how it ws her who farted and then she performs a fart at the end of the song (fake)
The foul chicks song in their video and on their myspace profile sings about them farting.
That is all i know
I'd be curious to find out some more information myself.