IBM Plans Web Meeting Service; Takes Aim at WebEx  NEW YORK (Reuters) - IBM &lt;A HREF="http://www.reuters.co.uk/financeQuoteLookup.jhtml?ticker=IBM.N qtype=sym infotype=info qcat=news"&gt;IBM.N&lt;/A&gt; plans to offer  Web-conferencing as a hosted Internet service, seeking to reach  small and medium-sized business customers while taking on more  established rivals in the market, the company said on Tuesday.