I'm not quite sure what you are getting at. Is it simply a matter of displaying a 2d image somewhere in the 3d space? (If so this is often achieved by texturing a plain object).
Or do you mean to make a 3d mesh out of a heightmap? (If so a good starting point might be to search for "memblock terrains" or similar, since they pretty much do just that. Once you get the hang of it using pixel data as input for the vertex heights shouldn't be hard).
Or, probably you meant something else entirely?
"Why do programmers get Halloween and Christmas mixed up?" Because Oct(31) = Dec(25)
