Making calls from Hangouts — in Gmail and across the web
Google rolling out voice calling through its Hangouts messaging service. Basically, it works just like video calling — you can call one person or many with a click of a button in Google+, Gmail, or the Chrome extension, and the wacky Hangouts effects are even in play — except it allows you to call phone numbers. You can even mix and match video and voice calling, so your friends without Hangouts won't be shut out of your chatting. Eg. you can add multiple phone numbers and video participants to the same call; and you can play sound effects (like applause or laughter) with the Google Effects app.
Calls are free to the US and Canada, no matter what country you're calling from, and impressively cheap elsewhere around the world.
To make a call from Hangouts, just look for the new phone icon in Gmail, or for the new "Call a phone" menu item in Google+ and the Chrome extension. And of course: if you haven't yet tried Hangouts in Gmail, you can always click your profile photo in the chat list and select "Try the new Hangouts."
Making calls from Hangouts is rolling out over the next couple of days. As google said before: "Hangouts is designed to be the future of Google Voice, and making and receiving calls is just the beginning". So stay tuned for future updates.