Incidentally, there is a post I did some time (way) back:
It’s a map generator application that I used to design the fractals for Mythruna’s terrain (and I use it for tons of similar stuff as well). It can be fun to play with just because it’s in many cases a direct implementation of a lot of the ideas in the terrain sections of the Texturing and Modeling book already mentioned.
From that thread, a screen shot of the editor with Mythruna’s settings:
