Nearly two years after acquiring Grand Central, Google is accepting some new users to its Google Voice service.

Based on Grand Central's technology, Google Voice gives users one phone number that will ring phones at work, home and mobile devices.

Additionally, it includes a central voicemail box that is accessible online, where users can search through transcripts of messages.

In March, Google said it would soon open the service to new users and let people request an invitation to start using it. On Thursday it said it started sending e-mails out to those people with instructions for signing up.

Anyone else can also now apply for an invitation. Google did not say how many new customers it will allow at this time.

Fans of the popular Grand Central service had begun to worry that the offering might die since it had languished for so long after Google acquired the service, only supporting the former Grand Central customers.

When Grand Central first emerged, it offered a number of unique services, some of which have since been replicated by other providers.

In addition to having a centralized phone number, users can listen to voicemail messages live, in the way people once commonly screened messages left on answering machines.

Users can also search through SMS (Short Message Service), with messages sent to mobile phones and then stored online.

One catch is that users of Google Voice must choose a new phone number to be their one line. Google is promoting that as a positive, suggesting that people look for new numbers that spell their name or other words.