How do you deal with Skin Thieves?

[Jaxel]

I often browse other people's forums... just to get ideas of the aesthetics of my own forums... But I was browsing through some forums of people responding on the Video-Directory mod when I realised that one of these forums had blatantly stolen one of my forum skins! Didn't even do it right, it looks ugly... and didn't even give my website any credit either.

My Forum: http://www.8wayrun.com/index.php?styleid=4
Stolen Skin: *** Removed ***
User: *** Removed ***

So how do you deal with something like this? This guy was emailing two weeks ago, asking if he could use my skin and if I would send him the PSDs. But I turned him down... yet he stole my skin anyways.