Mobile phones offer plenty more than just voice these days. They can provide news, video clips, local weather and even restaurant recommendations. That’s where companies like Google and Yahoo, along with a slew of start-ups such as InfoSpace, JumpTap and Medio, see a big opportunity. Mobile search and the advertising business models that have been proposed to support the service are sure to be hot topics discussed during the Cellular Telecommunications & Internet Association’s semiannual trade show.