Settings for lightning pictures with a Nikon D3100?

I plan on going out to take lightning pictures later on tonight and I was wondering what your opinion is on what settings I should use in Manual mode. I know I will need a long shutter speed, but I'm not sure what is a good one to stay at. All help is appreciated.

-- Thanks!

This may answer a bunch of your questions.

http://www.lightningphotography.com/tips.html