If we want to search for files in google, we don't want any web pages, luckily almost all files include "index of" in their path name, so you use intitle:"index.of" (the dot represents a spacing character like <space>, <underscore> or <dot>)
To narrow down the search results you can specify the extensions you are looking for with "(ext1|ext2|...)"
And as a final touch, if any webpages slip through a "-html -htm -asp -php -jsp" will squash them
All you have to add now is the thing you want to search for.
Example:
intitle:"index.of" (mp3|wma) American.Idiot -html -htm -asp -php -jsp Never thought it was that simple
[offtopic] WTF happend to the [url] tag? ...[/offtopic]
As you can see, this allows one to search for copyrighted content easily, especially music, since a lot of people have their music collection online
But if you want you can find software, games and videos (for the last one, you're be better of with a movie forum...)
Of course this brings up the question how legal google is... So far I've only used it to download 'illegal' material
Btw, I found out about it while browsing youtube videos
