Bottle Glasses

I've seen these in a lot of places and have always wanted to get some but today I found a tutorial on how to make them. It seems like you only need one tool which is relatively inexpensive (which I've added to my amazon wishlist :p) and sandpaper and hot and cold water.
These ones look lovely and I'm always tempted to buy beers with interesting bottles just to try them, so this would be a good excuse!
tutorial