A couple key quotes: "The UN says that private expeditions count as national activities and are covered by the treaty, which has been signed by all the major players. Lawyers disagreed and a second agreement - the 1979 International Moon Treaty - was drawn up to explicitly ban private ownership of lunar real estate." -http://www.guardian.co.uk/science/2005/oct/24/spaceexplorati...
"the activities of non-governmental entities in outer space, including the moon and other celestial bodies, shall require authorization and continuing supervision by the appropriate State Party to the Treaty" - http://en.wikipedia.org/wiki/Outer_Space_Treaty
Some good articles on trying to use the moon for private gain: