Here's a wide-field photo of a lightning strike near my home.
The method used was to set up the camera on a tripod, facing towards the lightning activity. I utilized the Shutter Priority mode on this occasion, setting the shutter speed to 20 seconds and letting the camera decide the best aperture. I had the 18-50mm lens set to 18mm to get the widest view possible. Using an infra-red remote, I shot multiple 20 second exposures until I was able to capture some lightning.
The image below is the best one for the night, taken as the storm moved away.
Click on the image for the full version.