Electronic cigarettes? What will they think of next?

I read about electronic cigarettes today and now I have heard of everything. I guess it could come in handy if you are looking for an easy way to smoke. I'm just kind of shocked because that is the last thing I would think could be made electronic. Now my question is how do they really do it? It has to be a very intelligent set up. I don't smoke, but I think I would really like to see how one works.