90.5 million acres of corn planted
This constitutes a 15% increase from 2006 and the largest corn planting in over 60 years. The demand for corn is being driven largely by the use of corn to produce ethanol (though other types of plants have greater ethanol yields in other places, like sugar cane in Brazil.)
Since farming is something of a zero sum game, other species of crops will decrease as a natural consequence of the bull run on corn, notably soy beans which have decreased to 67.1M acres in 2007. The US Department of Agriculture released a report this morning detailing these shifts and more.