I talked with a lady who did her Masters thesis on the Mayan calendar system a few years ago. I asked how the Mayans looked at the 2012 date. She said the Mayans believed in many earth ages, and that is only the end of this one, that there will be more infinitum, just as there have many in the past.
This earth may last forever, but man's order of things upon it will not, and there's the difference, because Peter compared the end of this world with the end of "the world that then was" in 2 Peter 3. The major difference is this world is to be destroyed by fire (God's consuming fire). The word "elements" in 2 Peter 3:10 actually means a time or 'orderly arrangement', and not this earth literally being destroyed.
The 2012 date may signal the start of the end, but we're not to pay attention to dates, but to the events, times and seasons (wider periods, not a specific day), written in God's Word. Before God's Word was given through Moses, It was written in the stars. The Christian scholar E.W. Bullinger in his work 'The Witness to the Stars' showed that, going back to ancient history for the original names and meanings of the star constellations before paganism corrupted them. The original meanings are associated with Biblical events.