Handset Makers Raising Virus Defenses  HELSINKI (Reuters) - Software security companies and  handset makers, including Finland's Nokia &lt;A HREF="http://www.reuters.co.uk/financeQuoteLookup.jhtml?ticker=NOK1V.HE qtype=sym infotype=info qcat=news"&gt;NOK1V.HE&lt;/A&gt;, are  gearing up to launch products intended to secure cell phones  from variants of the Internet viruses that have become a  scourge for personal computer users.