Google has just added Google Voice to Gmail, adding Voice over IP to the video/audio chat option and allowing you to call any phone number directly from your Gmail account page. Calls to the USA and Canada are free, and international calls start at 2 cents a minute. If you aren't in America, though, you don't get this new feature, presumably because Google has no agreement to use phone numbers in any other country.
Setup should be relatively easy. I had some hassle with Adobe Air suddenly popping up and crashing all over the place, but that seems to have sorted itself out now. Probably a result of running old software or the wrong software or both, on my old laptop. It all seems OK now and I had no trouble creating a Google phone number for myself (which will ring all your real-world phones, if you want it to).
If anyone's enthusiastic enough to post a comment, what do you think about this new feature? Google can transcribe your messages already, are you at all concerned that Google will now be able to scan your conversations for nefarious purposes in future? It already has the capability to record every interaction you have with any of the Google services, so why not take it a step further?
Note that secretly recording a phone conversation is illegal in most places and can get you into serious trouble, though I doubt very much if this will also apply to Google scanning a call without actually recording it or having a real person listen to it.
