SBC to Use WiFi Network to Extend Cingular Reach  LAS VEGAS (Reuters) - SBC Communications Inc. &lt;A HREF="http://www.reuters.co.uk/financeQuoteLookup.jhtml?ticker=SBC.N qtype=sym infotype=info qcat=news"&gt;SBC.N&lt;/A&gt; will  use its growing roster of public Wi-Fi access points as a  springboard for Cingular Wireless services, including advanced  phones and voice services using Internet technology.