Xbox Moon Money, Ballmer Bucks or Microsoft Points, whatever you called them, they are now finally gone.
After you update your Xbox 360 system software (which includes a few other tweaks), prices should be listed in good old fashioned local currency. Those with a Microsoft Points in their account or unredeemed cards will see their points be converted to an amount equal or greater to the points value.
Microsoft put together an FAQ right here to help better explain the transfer.