Mom Cummings found this in one of her magazines. We did it in her yard, and it turned out so great, that I did two of them in my yard. Here is the basic premis:
Drive a piece of steel rebar into the ground (I used a 5' long piece of .5" rebar from Home Depot). Don't go too far because you can't really pull it up without sacrificing a lot of stability.
Once you have the Rebar in the ground, add clay pots (the ones with a hole in the center of the bottom) alternating the direction of each one. Once you get them on, check the rebar and if you need to drive it a little bit deeper, take the pots off, hammer it in a little more and then check again.
Most people recomend larger pots on the bottom with same size or smaller pots on top. They even recomend a much larger pot on the bottom, and that it should go on flat, fill it with soil and then add the tipping pots. My rocks and planting bed can take it at any angle so I just started with the first one tipped. When I was checking it out online, I even saw one of these hanging on a rope instead of rebar in the ground, it was pretty cool.
We used some moisture control potting soil since the water will just run out of that little hole. it has pearlite in it to trap the water before it runs out the bottom of the pot.
This should be a fun way to have some fresh herbs all summer, and then the pots can come indoors at the end of the season so we can over winter them.