The idea behind Google Voice is pretty simple. Basically, it gives you one centralized phone number. When someone calls you on that phone number, it rings all of your phones. The beauty is the simplicity of the idea, but the genius behind it is in the execution.

Google Voice allows you to give out one phone number, but it’s a lot more than that. It also gives you a centralized voicemail box. And you can have it transcribe voicemails automatically, so that you receive in email the text of the voicemail. Pretty cool. Vonage charges extra for that feature.

And you can setup the service to ring several numbers, such as your home phone, your cell phone, and your work phone. But you can limit which hours an individual number rings. So if you don’t want your work phone to ring on the weekends simply block out those times.

The service was originally called GrandCentral until Google bought the company. It’s a handy tool with a lot of power backing up a deceptively simple idea. I’ve been using the service for a couple of months now and can recommend it wholeheartedly.

And if you have a smartphone such as a Blackberry or an Android phone, then you can run a Google Voice application that will allow you to call out from your Google Voice phone number. One point to keep in mind is that Google Voice doesn’t interfere with the operation of your already existing phone numbers. It’s essentially a routing service. But people will still be able to call you the existing numbers if they know them.

Google Voice is a productivity enhancer. It has some filtering features that can keep down on the phone calls. You can have it pass through Caller ID information, but also send unknown callers directly to voicemail. You can also require people to state their name if they’re not in your address book. Google Voice can tie into your Gmail contacts, or you can keep a list of accepted callers on the service.

Overall, Google Voice works as advertised. It’s mightily useful for people who want to consolidate their phone numbers and for people who receive a lot of phone calls. There is no charge for the service, but there are per minute fees for international calls. Otherwise it’s completely free to use. So go to Google Voice and try it out.