Earlier this week, Google announced it had agreed to purchase mobile display advertising firm AdMob, for an undisclosed amount rumored to be in the $750 million range. Well, apparently the shopping spree didn't stop there as the search giant is now putting down another $30 million for VoIP provider Gizmo5, which employs the SIP protocol to allow users to place calls over the internet.

Google has yet to formally announce the buyout, but many industry watchers think it is a done deal. If true, the acquisition could potentially provide integration across the company's communications tools, like Google Talk and Google Voice, which would result in users being able to make and receive calls to landlines and mobile phones.

It would also see Google compete directly with established VoIP call providers, such as Skype. Besides potentially turning the Google Voice platform into a more robust communications offering, recently leaked documents suggest the company may take the service global shortly.