On its altruistic quest for world domination, Google has merged Google Voice with Gmail, allowing users to make phone calls to any number directly from the browser.

According to neowin, Google will be rolling out the feature progressively in the U.S. and Canada over the next few days. Or you can install the Google Voice plugin now, allowing you to make free calls to anyone in the U.S. or Canada, and 2-cent-per-minute calls to 30 select countries.

The feature will allow users to receive calls right in Gmail, too, with their Google Voice phone number. TechCrunch is reporting that "call quality is very, very good – comparable to Skype." TC has a short video demonstrating the new functionality.

For the uninitiated, Google Voice is a (mostly) free phone service and allows users to choose one number for up to six different devices. You can use the same number for a mobile phone, home phone, and work phone, having all phones ring at the same time, or having none of them ring. Voicemails that others leave you are automatically transcribed to text and are forwarded to your e-mail.

The newly integrated Google Voice will also support video chat.

At the same press conference that it announced the new functionality, Google also unveiled plans to install U.K.-style red phone booths across universities and airports to promote Google Voice. Users will be able to make free calls from the booths, which employ Google Voice, to anywhere in the world. The booths are a way for the California-based tech company to show off the the voice quality of the service compared to other VoIP and landline-based phones.

Google did not say how many phone booths it plans to install or release specific locations. Look for more details in the coming weeks.