Gmail is integrating Google Voice and providing free calls to the U.S. and Canada, as well as cheap international calls, directly into Gmail.
Here’s the word from Google:
Calls to the U.S. and Canada will be free for at least the rest of the year and calls to other countries will be billed at our very low rates. We worked hard to make these rates really cheap (see comparison table) with calls to the U.K., France, Germany, China, Japan-and many more countries-for as little as $0.02 per minute.
As soon as it’s available in your account, you’ll see a Call phone link in the Chat sidebar of Gmail. Click it, search for a contact or dial their number, and booya—phone call. If you’ve already got a Google Voice number, calls you make from Gmail will show your Voice number in that person’s caller ID. You can also receive calls (if you want) made to your Voice number directly in Gmail—making it a fully functional VoIP solution.
You’ll need to have installed the Voice and Video plug-in to use it. No support for Google Apps accounts yet but Google says they’re working on it.