U.S. Stocks Close Higher as Crude Falls &lt;p&gt;&lt;/p&gt;&lt;p&gt; By Megan Davies&lt;/p&gt;&lt;p&gt; NEW YORK (Reuters) - U.S. blue chips closed at two-monthhighs on Tuesday as a fall in oil prices eased concerns thathigh energy costs would hurt corporate profits, but there wassome caution as investors awaited a speech by Federal ReserveChairman Alan Greenspan on Wednesday.&lt;/p&gt;