Check out this video tutorial to see how to remove and install a rear sway bar on a Honda Civic EP3 (SI or SIR). This may be the same on other vehicles.
You will need a 5mm allen wrench, a 14mm wrench, a long nose vise grip, and a 12mm socket with a long extension. Some lube might help you out, too.
Loosen the tire wheel nuts and jack the car up. Then just watch the video to see how to get that rear sway bar off of your automobile, or specifically, a Honda Civic EP3.