In photoshop you can "fake" a heightmap with the lighting effects.

Start by painting a new layer black and then set your paintbrush to a soft edge and maybe 10% opacity. Start painting in the hills. Each pass over the hills makes it whiter. And the heightmap uses the brightness of the layer to interpret the height of that particular pixel. Use the blur and sharpen brushes liberally to get the effects you want. Copy your layer into a new channel. Make a new layer that's 50% gray, then apply a lighting effect filter on it. Set the blending mode to "overlay" and presto near instant terrain.

I used it on a worldmap scale and used the Clouds filter to randomly generate a worldmap in this thread: http://www.cartographersguild.com/showthread.php?p=9640