Depth Mapping in 2.5+ (for creating brushes)

Hi, I’m looking for a good tutorial on how to make a depth map in blender 2.5 or 2.6.
All the tutorials on depth maps seem to be for 2.49-something. And the only similar tutorials I can find on this are for DOF. But I don’t want to create DOF… I want to turn these depth mapped geometries into brushes to then use in Sculpt Mode.

So how can I create a render that is just a black and white gradient that serves as a map for depth information?

It just occurred to me - I think part of the problem is that I was searching “depth map” when I should have been searching “height map”.
I was thinking in the wrong axis!

Easy to do in Blender since it uses an unconventional axis orientation, haha!
(Hey man, think different…)