Has Google found the final piece of its voice-calling puzzle? Rumors have it that the acquisition-happy search giant has acquired Gizmo5, a Skype-like VoIP startup. TechCrunch is reporting that Google has plunked down $30 million in cash for Gizmo5, which offers a software app that lets you make free phone calls to other Gizmo users, as well as inexpensive calls to landlines and cell phones. It supports SMS and instant messaging, too.

Google has yet to formally announce a Gizmo5 buyout, but many industry watchers think acquisition is a done deal. A Google spokesperson on Monday told PC World that the company doesn't "comment on rumor or speculation."

Andy Abramson, author of the VoIP Watch blog, sees the Gizmo5 acquisition as a key component of Google's overall voice stra tegy. The VoIP startup's technology provides Google with a PSTN link, or a means of enabling inbound and outbound calls to convention landline and cell phones. By integrating Gizmo5's tech with Google Voice, a clever call-management app that provides one number for all of your phones, and the Google Talk voice/chat client, a powerful phone service is born.

"If you put all of this stuff together, you have something a lot more powerful than Skype," Abramson says. "Google has just gotten to where Skype wants to go a little faster, assuming the deal is done."

Free Phone Service Coming?

So how might Google integrate the various pieces of its voice puzzle? And how might consumers benefit?

Given Google tendancy to stir up trouble in established tech markets -- just ask GPS mapping firms Garmin and TomTom -- a free, ad-support phone service doesn't seem too far-fetched.

"Google has a very deep investment in voice search, features that enable people to say, 'find this, find that,' and then make a phone call," Abramson says.

"Let's face it, with the phone companies monopolizing (voice calling), Google could come in and say, 'Hey, we'll give you phone service that costs nothing, and that's driven by our advertising revenue,'" he adds.

One thing's for certain: Voice will soon get a lot more interesting.

Contact Jeff Bertolucci via Twitter (@jbertolucci) or at jbertolucci.blogspot.com.