i agree with delay shutter i used 1/1000 shutter speed at 1600 iso on the following pic with just a normal tripod. on manual mode of course and yes focus to infinity and set lens focus mode to manual as well.
also try to shoot the moon when its not full because you need the shadows to create contrast/definition if you check my galley the metadata should be there.
On my first attempt at photographing the moon, I hadn't turned off the Active-D Lighting and wound up with some funky looking shots. ::what:: The moon looked much better when it was turned off.