We were just talking about lightning the other day, and I ran into this article on Engadget:
The article is talking about the Blitzortung.org website.
A better implementation of the map is located at:
Some apps for your phone do exist, too.
This is cool because I was just wishing that I had a way to determine how close the lightning was. We were swimming and watching the storms brew trying to figure out when we needed to get out of the pool. I wished that I had an alarm that would alert me when the lightning was too close for safety. I think the first Android app on their list might take care of that wish!