A scientific, but not overly technical, explanation of how lightning works:
http://science.howstuffworks.com/lightning.htm
Answers to scientific questions about lightning:
http://www.nssl.noaa.gov/primer/lightning/ltg_basics.html
A simple, interactive explanation of lightning and lightning strikes:
http://environment.nationalgeographic.com/environment/natural-disasters/lightning-interactive.html
An explanation of why most lightning storms occur in the summer:
http://science.howstuffworks.com/question646.htm
Lots of lightning information including a history of the study of lightning, how to stay safe during a lightning storm, and even your odds of being personally struck by lightning during your lifetime:
http://www.lightningsafety.noaa.gov/overview.htm
Lightning safety and information for kids:
http://www.lightningsafety.noaa.gov/kids.htm
