Google last month reserved 1 million phone numbers with Level 3, signaling that it may finally be ready to roll out its long-anticipated Google Voice service.

The free service, announced in March, lets users unify their phone numbers, allowing them to have a single number through Google Voice that rings a call through to all their phones.

Sources could not say when the 1 million numbers may be assigned. Level 3 has been supplying Google with phone numbers since the introduction of Google Voice, so the 1 million numbers are an indication Google is close to adding a significant amount of users.

A Google spokesperson would only say "as a matter of policy, we typically do not comment on contracts with third-party technology suppliers."

A public launch has been anticipated since Google said in March the service would be "open to new users soon." There has been speculation that the service would begin today – June 18 – but Google has yet to make an announcement.

"I've only been using Google Voice for a few months, but it's completely changed the way I use voicemail and communicate, just in general," said Kevin Dando, director of digital and education communications for PBS. "When it goes public, I think the rush to grab Google Voice numbers is going to be stunning. I know some of my friends check the Google Voice page almost every day to see when they can grab a number and get started using it."

Google Voice has a number of unique features including call transfer between a user's devices, multi-party conferencing, conversion of voice calls to text messages, cut-rate international calling, and call transcription.

Google also has integrated the Voice service with Gmail contact lists.

But the gem is the fact that a user can have one phone number people can dial to reach them regardless of where they are located, either home or mobile. Google Voice uses VoIP to link collections of phone numbers.

Google Voice is a product of Google's March 2007 acquisition of GrandCentral. For the past two years, however, it appeared the GrandCentral technology had been tossed into a black hole.

But on March 11, Google announced Google Voice and opened the service up only to former GrandCentral users.

Last week, TechCrunch reported that Google would add number portability later this year to Google Voice, which would let users keep one of their existing phone numbers as their Google Voice number. For example, users could make their cell phone number their Google Voice number.

The feature is significant because switching to a new Google Voice number comes with a cost such as having to distribute the new number to friends and family. In addition, outbound calls and text messages show the phone number you are calling from and not your Google Voice number.

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This story, "Google Grabs 1 Million Phone Numbers for Google Voice" was originally published by Network World .