Vile, the settings are simple, and Doug is right, no sky-lab sun... Just create a spotlight, and position it, then create a basic sphere, set it to "Hidden", and put it where you want the spotlight to point to. Then "Track" the light to the sphere, and in the light settings set it to "VOlume Visible" and "Infinite Light", turn the falloff to like 20, and the light however high you need it. The other thing, is if you're not experiencing this effect, is it is sometimes necessary to put in another light, say a radial, to illuminate your volume better. This extra light can go anywhere, but I like them best right behind my spotlights. WIth the acacia plant, it had a radial light right in FRONT of the spotlight... THe radial light is set pretty low, maybe around 10. Just some ideas!