There don't seem to be many good lightning models around, so here is my attempt...
It is controlled by an armature of 3 bones - one to aim the stem of the lightning, one to aim the forks, and one to turn the lightning on and off. Hopefully this will make using this model to create multiple lightning strikes fairly fast.
See it in action here: http://www.blendswap.com/blends/view/69013
Forgot to add a video link:- https://www.youtube.com/watch?v=FIbDCVx-2Ak