Again, like so many other treatments, massage is often applied in combination with other treatments, especially stretching. To treat heel spur/ plantar fasciitis, the massage is usually applied to the calf muscles, so that they become less stiff, the blood circulation is stimulated and they become more relaxed. Relaxing the calf muscles lessens the strain on the fascia under the foot, also relieving the heelspur.
Besides classical massage, which should be performed by a professional, you can easily apply some massage exercises yourself. One method is to take a golf ball or tennis ball, and to roll this beneath the foot. This can easily be combined with desk-work. Quite a number of patients have reported this as a successful method against heelspur.
See also this video (courtesy of sportsinjuryclinic.net):