The perfect torch

i'm planning to add an ultra cool dungeon to hhexen. and every dungeon needs flickering torches that are burning forever for no reason without using oxygen. of course the torch should cast moving shadows (easy: little random lightsource movements), but the light should also be flickering, change the color etc.

also, each torch should only affect a certain range. how can i do this? the light i'm using for the landscape is a simple directional one and i have no experience with this kind of lighting.

Why not using a simple PointLight with a quadratic attenuation big enough?

because i have no idea about what a light can and can't do. i'll try it and see what happens.

While at it, can somebody provide the formula to convert radius based light attenuation to the opengl fractional one?