New Lead for Fireball Riddle - A BBC news article on New Zealand scientists who believe that ball lightning is little more than burning soil fragments that have been kicked up into the air.
Scientific American: Ask the Experts: Ball Lightning - According to a statistical investigation, approximately 5% of the world population have witnessed ball lightning. Various physical theories are presented here.
Atmospheric Electricity - A meta-reference general page about Atmospheric Electricity, with a bibliography and links.