well, it kinda works like a bump map. Gotta have the displacment map in grayscale, a bmp usually works best for that. Then, all you should need to do is apply the thing and control it in the att. editor. Just, start it with a very minimal number and work up from there, since it does actually create geometry using the map. A high setting will blow it way out of proportion and take forever to test render.
Dave Baer
Professor of Digital Arts
Digital Media Arts College
Boca Raton, Florida
dbaer@dmac.edu