Google hath tweeted that their new integrated Gmail calling feature announced yesterday has already seen 1,000,000 phone calls placed in just under 24-hours. The new service allows users to place VoIP calls — right from within the browser — to the U.S. and Canada free of charge and for very affordable rates to other countries around the world. We’ve been playing with the new feature and we have to say, it’s pretty impressive. Have you tried it? Thoughts?