Auto-Add MP3's from a folder to iTunes Playlist..

[needsomehelp]

So I posed this question before but didn't get an answer I was looking for. After some research, this is what I found:

http://www.macosxhints.com/article.php?story=20070301051316596

Anyway, my problem is, I want iTunes to automatically update a certain playlist whenever I add a new song to a certain folder. So lets say I add a new song to my "ROCK" folder. I don't want to go to iTunes and update my ROCK playlist each time. I want iTunes to do it itself. That's what I believe that the above link tried to accomplish. However, I don't understand how to link the script to my mp3 folder as the link above suggests.

Any ideas?

Thanks