Making a fog shader

:confused2: What shader template should i use to make fog with. I'm trying to make fog that goes under my water so it look more natural. Also how would i put the fog into the map, would i use a plane or a box. I have zip idea how to make fog so all help and any insights will be helpful.

THANKSSSS:):):)

...Again i would search the forums but i cant search 'fog' cuz its only 3 letters. Google didn't give me anything either.

http://www.h2vista.net/forums/showthread.php?t=3896

thats for water, how do u do fog, i mean shader-wize.

sigh, it is for all shaders, just ask there. It just got kinda consumed as a water shader thread.