heya; first of all, if you have a fire material and a smoke material, you mix them. at the start of the animation, you set the slider to all material #1 (fire), and at the end, set it to all #2 (smoke). see the frog-to-stone tutorial. now, as to making the flames wiggle and sputter and do flame-like things.... er... experiment? :) i think you want to mess with the turbulence of the orange-to-yellow gradient mix function. just set it at one value at the start and another value at the end and see what that does.