Step 1: Assemble materials
Now everything depends on what size garbage can you select - if you get a really big one, you'll need to cut your wood into larger pieces in order to build a big enough frame to allow your can (once it's been suspended by the rebar or PVC tubing) to swing a full 360 degrees without hitting any part of the frame. So buy your garbage can and then figure out what size wood pieces you'll need in order to build a big enough frame. I bough a 35 gallon can for $14.99 and it probably doesn't make sense to go any smaller than that.
Step 2: Build the frame
Step 3: Prepare the garbage can
Then drill lots of holes all over the garbage can to provide aeration to the bacteria that will be composting your waste.
Finally, and this is the slightly tricky part, you'll need to cut a 'door' into the body of the garbage can into which you'll place waste and out of which you'll hopefully extract usable compost. If you're using a jigsaw, I suggest setting the bevel to 45 degrees so that the blade is tilted towards the center of the door. This will help to form a tight seal and not let compost spill out when you're spinning it around later. After you've made the cut, attach hinges to one side and some mechanism for keeping it closed on the other. I also attached some little metal plates on the top and bottom sides of the door just to keep it nice and secure.
Step 4: Hang the can
I then passed the rebar through one end of the support, through both ends of the can, and then through the other end of the support. And voila!
Check to make sure it's sturdy and that you can swing the can a full 360 degrees without any obstructions.
Have fun composting!