Hi there,
I was able to get a TerrainPage (plan to replace it with this kind of super-terrain currently in development) up&running and place an moveable object into it, very much like the flagrush tutorial.
What I would like to archieve is lightening, so that e.g. my character is darker when I drive e.g. into another model, e.g. a hole or a tunnel and that I see a shadow of my model on the terrain.
Furthermore I use a shader to to texture splatting on the terrain, does this mean all the cheap fix-function stuff needs to be replaced by self wrtten shader stuff?
I am really unexperienced when it comes to 3d at all, maybe you can give me links, explaining everything would be a waste of your time I guess 
Thank you many times, Clemens
jME has shadows, flagrush deals with this too. For making your character dark or light, give your model a lightstate and attach some lights to that. This is probably also covered in the tutorials, except there they attach these to the top node (rootNode) so the light gets applied to the whole scene.