This is a popular entry in the Instructables Green Design Contest by HomeMade Modern. (Another of their entries is the DIY rustic log lounge chair which has had TreeHugger readers talking.) Like that chair, this entire hanging garden project can be done in half a day, for about $30.
All you need for supplies are 1/4" copper tubing, a glass cutter, some glass wine bottles, Goo Gone for getting the labels off the glass, wire cutters, a drill, and some sand paper (and of course safety goggles and gloves).
Here's a video showing the basic steps, though the Instructable also provides photos and text for each part of the project.