Exxon Mobil to Take Charge  NEW YORK (Reuters) - Exxon Mobil Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=XOM.N target=/stocks/quickinfo/fullquote"&gt;XOM.N&lt;/A&gt;, the world's  largest publicly traded oil company, said on Friday it would  take a charge of \$550 million in the third quarter to cover  claims from gas station owners who sued the company for fuel  overcharges.