You know those baby corns you find at salad bars and in some chinese food? Are they really corn or some unrelated but morpholcogically similar vegetable? Are there corn fields somewhere the reach up to ones ankle?
They are just normal corn harvested before the ears mature. Some varieties of corn work better than others.
Directions on growing your own:
http://eesc.orst.edu/agcomwebfile/garden/vegetable/babycorn.html