It's called bowtie just google it, its a free application that displays your music being played in itunes. There are lot of different mods for the displays but you get some standard ones. Hope that helped.
To be honest, I don't like that specific icon you linked me to. First, I have no reason to use it. And second, it looks to much like an image. I know that's what it is, but it doesn't look like a real icon to me. This guy has nice icons, but I don't think I would use any of them.