__Artifex Terra - Height map editor and painter for terrain. __
Free software, using the Ogre engine and the ((ETM|Editable Terrain Manager)).
Features: artpad support, brush-system, texture painting/editing, colour painting, sculpting tools, terrain and colour filters, ogre object placement and editing. Exports heightmap, colourmap, lightmap and coveragemaps separately.
Details in this [http://www.ogre3d.org/forums/viewtopic.php?t=42507|forum thread].
__Todo: Copy screenshot + details from forum to this page.__