1) the US and other major space nations never signed on to the Moon Treaty. Very few have.**
2) dup thread: http://www.neowin.ne...ander-proposal/
** Australia, Austria, Belgium, Chile, Kazakhstan, Lebanon, Mexico, Morocco, Netherlands, Pakistan, Peru, Philippines, Saudi Arabia, Turkey and Uruguay are parties to the treaty, 7 of which ratified and the rest acceded. France, Guatemala, India and Romania have signed but not ratified.
UN treaties still prevents anyone from laying claim to it.
I can't see this happening without some form of robust legal framework being established for it and can't imagine it'll be accepted by other governments as a free-for-all.
Edit: I see the US didn't sign a subset of the Outer Space Treaty because it was deemed anti-business lol.