Yahoo on Wednesday said it would add voice-enabled search to its mobile platform and rolled out a test version of the upcoming service as a download for users of Research In Motion's BlackBerry smartphone.

The new feature will be part of version 2.0 of Yahoo's OneSearch, which the company plans to roll out to mobile phone manufacturers in the summer. The upgrade was unveiled at the CTIA Wireless conference in Las Vegas.

OneSearch was launched more than a year ago as Yahoo's search platform for mobile phones. The upgrade improves on the original version by introducing voice-enabled searches, as well as features that deliver more information to queries than just links.

Marco Boerries, president of Yahoo Mobile, demonstrated OneSearch 2.0 during his CTIA keynote. Yahoo expects to make the service available directly on the home screen of select handsets through deals with manufacturers. Nokia has already committed to offering the service on its Series 60 phones, Boerries said. The application also would be available as a download on the Web for some phones, such as those running Microsoft's Windows Mobile. BlackBerry users could download the application as of Wednesday.

To access the voice service, a person would only have to push the call button on the phone and say a word or phrase to Yahoo's automated service to get results shipped to the phone. During the demo, saying "British Airways 287" got arrival times, "March Madness" got a list of scores for games played during the college basketball tournament, and "3600 Las Vegas Boulevard" led to a street map and directions.

Asking the question "Where's the best place to play craps in Vegas?" returned postings on the topic from Yahoo Answers, a forum in which users ask questions of other users. "We give you better answers than just Web links," Boerries said.

Yahoo also improved the "search assist" by showing possible results immediately as a person types a query. The results also contained more than just links. Results could include listings for news stories, graphics, and other content. Listings would also include a few words describing the available content.

If the search involves looking for a person, then the results would include those social networks in which the person's name is listed.

Yahoo plans to make money from OneSearch and other mobile services, such as e-mail and instant messaging, through advertising. Last August, Yahoo acquired Actionality, a German advertising company that provides software that inserts ads in content for mobile devices.

To drive adoption, Yahoo has taken an open approach in which users can access services from other portals through Yahoo's mobile platform.

Yahoo predicts that by 2010, there will be more than four times as many mobile devices in the world than PCs, Boerries said. In time, more people will access the internet through a mobile device than a PC. Today, however, people are 10 times more likely to use a PC than a mobile device.