Sony Launches MP3 Walkmans to Counter IPod  LONDON (Reuters) - Sony Corp &lt;A HREF="http://www.reuters.co.uk/financeQuoteLookup.jhtml?ticker=6758.T qtype=sym infotype=info qcat=news"&gt;6758.T&lt;/A&gt; launched its first  MP3-compatible flash memory digital music players under the  Walkman name on Monday in the latest bid to reclaim the lead in  a market it has lost to Apple Computer's iPod.