http://www.world-builders.org/
I did a forum search and only found one post mentioning it - that post being an intro thread from back in 2008. I've been finding it useful, myself, as I learn Fractal Terrains 3 even though some of the material is likely outdated.

It's the website for what was a class at Cal-State University, Los Angeles and it has structured lesson/subject oriented tutorials/links. Hope others find it as useful as I have. Mods, let me know if I've posted redundantly, and how I can better utilize the search function in the future when checking to make sure I'm not missing coverage somewhere else so I don't clutter up the forum.