• Set your camera on maximum resolution and the quality on 'FINE'.
• Set the zoom to the max and add one of the telephoto extenders if you have one.
  
• Set your colour balance for daylight.
  
• Change the metering mode to Manual.
  
• Set the shutter speed to 1/500th or 1/1000th - remember the moon is in full sunlight, a daylight shot.
  
• Stop the aperture all the way down.
  
• Try a shot. If it is too dark, open up the aperture two stops.
  
• Try a shot. If it is too dark, open up the aperture two stops. If it is too light, stop down one stop.
  

Aim for a slightly dark image with no burned out highlights. Not VERY DARK - just a little dark to ensure full detail. You can use the magnifier on Playback to examine the image between shots.

The moon will look rather small unless you are using telephoto extenders. This shot was taken with the 2x.

Bring into your image processing program of choice and crop away excess sky and use the histogram function to bring the brightest areas up to full maximum level.