The latest voice-activated Google Mobile application for the iPhone has finally arrived after an unexplained three-day delay. Moreover late Monday Google added voice capabilities to its search application for the iPhone. Google Mobile App 0.3.142 hit Apple's App Store, the only official online mart for iPhone software from third-party developers, on Monday. It can be downloaded free of charge.

And the most amazing thing about it is how well Google had implemented the new voice recognition feature, both in terms of its user interface and in how well it actually works. Te app automatically kicks off the voice recognition as soon as you bring the iPhone up to your ear (with the app running, of course). You then speak into the phone and remove it from your ear; the app recognizes what you said with great accuracy and immediately pulls up the search results.

Nevertheless the application is not perfect yet; when it comes to names and complex phrases the voice recognition messes things up a bit. But with some careful training of your own voice commands you can start to use Google Voice Search with more reliable results. Voice Search also works with your Contacts, so it could be used to quickly find people in your Address Book.

Raj Reddy, an artificial intelligence researcher at Carnegie Mellon University who has done pioneering work in voice recognition, said Google’s advantage in this field was the ability to store and analyze vast amounts of data. “It’s important to understand that machine recognition will never be perfect,” Mr. Reddy added. “The question is: how close can they come to human performance?” For Google the technology is critical to its next assault on the world of advertising. Google executives said location-based queries would make it possible to charge higher rates for advertisements from nearby businesses, for example, although it is not selling such ads now, according to The New York Times.

Please mind that while most of Google Mobile App and its text-based features will run on an iPod touch, the vocal search feature is only compatible with the iPhone for now, and only in English.

The narrow vocabulary for location searches that Google Mobile App is designed to work with as well as the fact that the application does not bring hands-free calling to the iPhone. The Google Mobile app gives you its answers in text, which makes for a very quick experience. If your result returns phone numbers, you can dial the phone by clicking on one. But if you're driving in your car and need a quick connection, use Goog411 instead, which is a full voice-in, voice-out experience. As others have noted, Google Mobile doesn't let you do voice dialing from your own contact list. It's frustrating to be able to search the entire Web with your voice but not be able to search your own phone. But still it is definitely worthwhile, so just give it a try.