The kettlebell swing is a great exercise for jacking up your heart rate and for strengthening your gluteals and hamstrings. However, I see it performed with poor technique all the time, making it a high-reward, high risk-exercise. Here is a brief tutorial on how to safely swing a kettlebell and get maximum benefit from this move.
Again, this a wonderful exercise to add to your routine. Just be sure that you are performing it properly. Swing in good health!