Well... first off, 2012 has zero to do with anything Nostradamus predicted.
All the 2012 hoopla stems from the fact that the completion of the thirteenth B'ak'tun cycle in the Long Count of the Maya calendar occurs on Dec. 12, 2012, and by Mayan beliefs, the end of a cycle marks a great change in mankind's existence. Some people interpret this as the apocalypse (despite the fact that we're current IN the 13th cycle, so obviously, nothing has happened the previous 12 times it ended).