-inurl:(htm|html|php) intitle:"index of" +"last modified" +"parent
directory" +description +size +(wma|mp3) "Nirvana"
Just replace Nirvana with a song or artist of your choice to display a
results page of indexes that contain downloadable MP3s.
P.S. Don't steal music.
I don't understand the purpose of this post - but it appears to have
been spammed on at least one other list. Anyway - as the audience
probably knows, http://johnny.ihackstuff.com/ is full of such tricks.
Of course it isn't a security issue which affects google - google is
just showing you want you want to see. Or maybe not .. sometimes ;)