Google is testing out a new feature that would make GMail more useful for communication. Google is integrating a VoIP service into GMail.
A new phone icon opens up a GMail chat window with a dialed. There is also an option to find contacts. Currently if you want to call someone with Google Voice, you need a phone. The way Google Voice works is that you visit the website through your computer, enter the phone number to call, and then wait until Google calls your phone to connect you for free.
Google created the Google Voice service through the acquisition of Gizmo5. Right now Google Voice on GMail is not available yet, but we can expect it to happen sometime soon.
[Google Operating System]