Google Voice is now available on BlackBerry and Android smartphones.
The company began sending invitations to join Google Voice last month, and today said an application for the two smartphone platforms is available.
Before today, BlackBerry and Android device users had to dial a Google Voice number from their phone, or online, to place a call.
The new apps allow users to make calls and send SMS with a Google Voice number directly from their Android or BlackBerry smartphone. The call can be made directly from the phone's address book because the app is integrated with the phone, Google said.
The application means a user can access voicemail, read SMS messages sent to Google Voice and access call history. Users can also place calls and send SMS messages. A video at Google's blog explains some of the functions.
The app is available to Android phone users at the Android Market, but BlackBerry users must download it from the Google Mobile site. Google Voice is by invitation only still, but Google said it is sending out invitations daily to those who have registered.
Google didn't indicate when Google Voice might be available for othr platforms such as the iPhone, Windows Mobile devices or Palm's WebOS. Some reports have indicated that Google is working on an iPhone version.
The news is significant, said analysts, because Google Voice is now available on at least one major mobile platform.
Anslyst Jeffrey Kagan, said the features of Google Voice are powerful, but he questioned how widely they will be used, since there are now so many choices for making calls and sending text messages.
With so many choices the marketplace is "both excited and confused," he said, noting that users can work with traditional carriers, but also third parties for VoIP calls from a wireless device.
The appearance of Google Voice on smartphones has led at least one prominent blogger, Om Malik, to suggest that Google could become a person's phone company.
More traditional vendors of unified communications gear, including Cisco Systems, have taken note of Google's role in communications as well.