You may be able to dial phone numbers and carry on voice conversations directly through Gmail Chat as early as Wednesday, when Google has scheduled an announcement.

The new service reportedly has a very Google Voice-like interface that uses similar icons for placed calls, missed calls and voicemail messages. But it's unclear whether the unnamed feature would be integrated with your Google Voice account, because you will not need a Google Voice phone number to use the new service. But just like Google Voice the new service will let you place free phone calls to the U.S. and Canada, according to a report from CNET.

It's unclear when any new Voice over Internet Protocol (VoIP) service would launch, but Fortune's Seth Weintraub expects Google's press briefing today to unveil the service then.

VoIP in Gmail

You can already use Gmail Chat to carry on voice and video conversations with other Gmail users, but so far you have had to turn to Skype or a similar service to make Web-based VoIP calls. A new voice calling service from Gmail would directly challenge the need for Skype, and is likely the result of Google's recent acquisi tions of VoIP provider Gizmo5 and VoIP codec developer Global IP solutions.

But questions still remain about whether this anticipated VoIP offering is related to Google Voice. While the interface for the new service is similar to that of Google Voice, direct dialing through Gmail would be a VoIP solution -- something that Google Voice is not. It's unclear, then, whether the two services would be integrated.

It's also not unusual for Google to duplicate functionality especially when it comes to communications. You can, for example, send SMS messages through Google Voice, but Gmail also has a separate SMS service.

Nevertheless, the whole point of Google Voice is to bring your voice mail, SMS messages, and calling history into one place. So Gmail Chat and Google Voice integration would make a lot of sense.

If the speculation is true, Gmail is about to become an even more indispensable Web-based productivity app than it already is.

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