The Open Source Threat Open-source software is nipping more sharply at the heels of Microsoft, leading the software giant to defend itself more fiercely than ever against the insurgent rise of freely distributed, collaboratively coded programs. &lt;FONT face="verdana,MS Sans Serif,arial,helvetica" size="-2"\ color="#666666"&gt;&lt;B&gt;-washingtonpost.com&lt;/B&gt;&lt;/FONT&gt;