That's a pretty old hoax, isn't it?
We may have had two at some point in the past, seeing as we've got a pretty atypical ball of rock here and a spare orbit and all that, but if we did, it's not there anymore.
Granted, there are some objects librating at our lagrange points, but those are not strictly speaking moons, and as far as I know they're not even close to that size (if they were, not only would the ones in the leading point be visible, but both the leading and trailing points would be a lot more thoroughly explored in order to attempt to break them up to more manageable sizes if there were even the slightest possibility of anything with that sort of mass being in an unfortunate slot).
"If God saw what any of us did that night, he didn't seem to mind.
From then on I knew: God doesn't make the world this way.
We do." -- Rorschack, Watchmen.