T-Mobile USA is set to launch <A HREF="http://news.yahoo.com/s/ap/20061006/ap_on_hi_te/t_mobile_wireless_voip;_ylt=Aog617JqqBySH7TGQQunDRSs0NUE;_ylu=X3oDMTA3cjE0b2MwBHNlYwM3Mzg-">a new breed of mobile phones</A> that can pass live phone calls between cellular and Wi-Fi networks, a top executive told The Associated Press on Friday. T-Mobile declined to disclose the specific market where they planned to introduce the technology, known as UMA or Unlicensed Mobile Access. UMA is designed to hand off calls without interruption from a cell network to a Wi-Fi router, or vice versa.