Google is finally catching up with competitors Microsoft and Yahoo for once. It is rolling out a new application for the iPhone that allows users to conduct searches with their voice rather than typing. Nice of Google to catch on to the voice-activated search craze.Microsoft and Yahoo have offered voice-enabled search for some time. Microsoft through its TellMe service and Yahoo through its oneSearch service. Both work pretty well at converting speech into text and delivering relevant results. This is a feature that Google's services have lacked for too long.

First to get Google's version of voice search is the iPhone. The New York Times reports that the application will be available through the iPhone Apps Store as early as today, though that isn't confirmed by Google or Apple.

The voice search application works like this:

• Users hold the phone to their ears as they would for a call.
• They speak their query into the headset.
• Google sends the speech data to servers for processing.
• Once the speech is converted to text, Google sends the text to its regular search servers.
• After the results are generated by Google, they are returned to the user.

The Times notes that, "The Google system is far from perfect, and it can return queries that appear as gibberish. Google executives declined to estimate how often the service gets it right, but they said they believed it was easily accurate enough to be useful to people who wanted to avoid tapping out their queries on the iPhone's touch-screen keyboard."

Voice recognition has come a long way in the past several years. Companies such as Nuance Communications provide speech-recognition services to a number of cellular network operators around the globe as well as software such as Dragon NaturallySpeaking. Nuance has one of the world's largest collections of human utterances in multiple languages and accents, which helps it return more accurate results. In demonstrations I've seen, Nuance's technology outperforms anything else, including TellMe and oneSearch. One of the engineers helping to create Google's voice-recognition services was a co-founder of Nuance, Mike Cohen.

Having this ability available to users of cellular phones is key. Voice technology will allow users to conduct searches without having to look at the device, which means they can pay attention to other tasks (such as driving, even though this would still be a no-no).

The application will be free for iPhone users. (I checked this morning, and it isn't available yet.) Google has not said if or when it will bring a similar service to other mobile platforms.