Description from original post (created 2009-06-17 17:48):
How to Steal Skins in MineCraft
Ahhh, MineCraft. An awesome game that lets you sandbox buildings. But while it’s very fun, the new skin feature seems to be very insecure. After wondering where raw PNGs were stored, I realized that it was imperative to have a uniform system based on confirmed username. This would help for the server, which has to display custom skins based on your particular username.
Fortunately, it was easier than I thought. The names were not even MD5′d or otherwise hashed to make it hard for us to detect. It wasn’t in a hidden folder. It was all public in minecraft.net/skin. What I mean : My raw custom skin PNG was stored in minecraft.net/skin/AlLnAtuRalX.png. Notch’s is in minecraft.net/skin/Notch.png. Easy right? Also fun… Everything is public domain now. Just see someone with a skin you like and grab it.
Notch's Custom Skin 
(Currently)
Notch, I tried to notify you, but you weren’t on IRC. Oh well… I have a feeling it’ll get fixed soon enough. Or hell, you can leave it. This is an awesome feature IMO, and I want people to use it. Download as many skins as you can before it gets sealed up forever!
Cheers,
AlLnAtuRalX
Reddit Public Server Admin
Blog Post Here
Enjoy guys.. Knock yourself out before it's fixed :wink.gif:.