Start to create a new image and choose MOON NIGHT in the atmospheres.
Then click at the little sun in the toolbar.
In the window what opens, choose NO VISIBLE SUN and click OK.
Now, create a sphere and map it with MOON material from the SPECIAL EFFECTS. Create a SPOTLIGHT and place it to light the "moon" from 1 side. You may try different positions for the spotlight to get the effect you want. At least, group the spere and the spotlight and move it away from te camera until you are satisfied.
Please mail critics and comments to me.