I posted new tutorials "Discovering Terragen 3" http://www.geekatplay.com/terragen.php
, you can also watch them at Youtube geekatplay channel,
New tutorials unlocked weekly to free watch, or you can always buy all them, to support site going.
Here is list of upcoming more tutorials:
Release : Discovering Terragen 3" - Beginners/intermediate level, over view off application and fast way to start working with it.
Coming soon: "Exploring Terragen" (multiple series" - Intermediate/Advanced, project based tutorials. Learn by example with in depth.
Coming soon: "Mastering Terragen" - Advanced, subject based on subjects, example: Mastering Highfield terrains, or Mastering Cloud Layers ...etc.
Terragen is professional complex application and it will take some time to cover all aspects, please let me know if you have any specific questions or suggestion.