A disgruntled network administrator <A HREF="http://www.infoworld.com/article/08/07/17/IT_administrator_pleads_not_guilty_to_network_tampering_1.html?source=rss&url=http://www.infoworld.com/article/08/07/17/IT_administrator_pleads_not_guilty_to_network_tampering_1.html">pled not guilty</A> Thursday to charges of computer tampering for allegedly setting up an unauthorized access system and holding much of the city of San Francisco's computer network hostage.