IBM Settles Part of Giant Pension Lawsuit  NEW YORK (Reuters) - International Business Machines Corp.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=IBM.N target=/stocks/quickinfo/fullquote"&gt;IBM.N&lt;/A&gt; has settled for an undisclosed sum part of a  potentially multi-billion-dollar lawsuit over its pension plan,  a Wednesday court filing shows.