Google has opened up Google Voice to users who have registered on its website. Previously the service was only available to former users of Grand Central, the company acquired by Google in 2007 and on whose service Google Voice is based. There is however no news as to when Google Voice will be available outside the US.

The company announced the availability of Google Voice on its press blog, "We are happy to share that Google Voice is beginning to open up beyond former GrandCentral users." Users will receive an invitation that allows them to pick a number that can be personalised. "See if you can find a number that contains your name, a specific word or a number combination," Google said on its blog.

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

A public launch has been anticipated since Google said in March the service would be "open to new users soon." Users who have been using the service have been talking up its benefits.

"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.