Voice recognition for cellphone Web searches is evolving

— -- The mobile Web provides many of the riches available to folks who surf from a PC. But searching for cyberpearls on tiny cellphone keyboards or touch-screens is challenging.

That's where mobile voice search comes in. I've been testing services from Google, Yahoo and start-ups ChaCha and Vlingo. They all let you seek information by merely asking out loud.

You may wonder if your flight is on time, what the weather will be when you get there or where to get dinner. Or you might want to settle a bet at a bar. What was Yogi Berra's career batting average? What's the safest SUV? What is absolute zero?

I posed these and other questions to test the services. Answers are supplied in different ways. With Google, you'll get links to Web pages. ChaCha, my favorite among these, relies on human beings to respond. Company "guides" surf on your behalf and text the answers within a few minutes.

Mobile search by voice isn't new, but it's rapidly evolving, and in many instances takes advantage of location-based information. In some instances, you can combine voice search with other capabilities, perhaps by summoning maps.

Google voice search is just now arriving on the T-Mobile G1 Android phone as part of a major software rollout. A version is already on the iPhone. And this week, Yahoo expanded its OneSearch with Voice offering beyond certain Nokias and BlackBerrys (I tested on a Pearl) by adding the capability to some Windows Mobile phones. Indeed, some voice search offerings work only on specific handsets. ChaCha works pretty much across the board.

None of the services are flawless. Half the battle is recognizing the question. The timbre of your voice, surrounding noises and cell coverage all have an impact. Brevity often sufficed. It was typically enough to say, "Weather, Aspen" or "American Airlines Flight 972" to get a forecast or flight status.

Assuming the question is understood, you expect prompt, meaningful and useful results. My experience was mixed. A closer look: