Google adds voice to Gmail; free calling to any number in the US

Today Google officially made use of their Gizmo5 acquisition by introducing free voice calling in Gmail. You'll be able to call any number in the US or Canada for free, and you can also make calls internationally pretty cheap. For those calls that do cost you some moolah, you can buy some credit with Google Checkout.

Not only will you be able to make calls from Gmail, but Google is making Google Voice, but Google is making Google Voice phone booths at an airport and a couple of universities.