Jogging on the spot, will raise your heart rate and has exercise value.  That being said however, there is more exercise value in running outdoors or on a treadmill.  Jogging on the spot, you have no value of distance, or the effort put forth, as to how much you've run or other running nuiances such as hills or dips.  Realisticlly too, your going to burn more energy on a full run, where you are lengthening you stride, as opposed to shifting your wieght from one foot to the other while jogging.  I personally only jog in place when waiting for the light to change while running in Chicago, and thats just to keep my heart rate up.  Hope it helps, run safe.