I'd like to share a tutorial for layered fog, which we're using in the
Inago Rage Beta Test. The images above show this fog in effect:
1) A scene with standard A6 fog
2) Fog planes added along ground level
3) Lighting added to accentuate the effect
4) Another scene with a thin series of fog planes
This is a really simple but nice effect; a tutorial is available
here.