Please consider the chart of the December 2010 futures contracts (24h):
UNG also reacts accordingly:
However, the January 2011 prices have also risne, thus has contango, so we know what will happen to UNG.
January 2011 contracts:
The contango Jan 2011 to Dec 2010 is now 3.8% (note: 4.3% as of 3PM)