Option 1:
Google Voice
Since September 2011, Google Voice is the very best
way to make free Internet phone calls. With Google
Voice, you can make free phone calls, free PC to
phone calls (via Google Talk browser plugin), and
free PC to PC calls (also via Google Talk).
Google
Voice is much more than a way to make free phone
calls on the Internet. Google Voice is primarily a
way to manage the phone numbers in your life and can
be used to intelligently route incoming calls to
your free phone number provided by Google Voice to
any other phone you have. With Google Voice, you can
also get free SMS, make a free conference call, and
get free voice mail services.
Free calls you make with Google Voice must be to
numbers in the United States or Canada.
Google Voice is available as a web app that you
can use in any browser, including mobile browsers
(as pictured here). Dedicated apps are available for
Android, BlackBerry, and iPhone users.
Free phone calls with Google Voice are limited to
three hours. However, you can continue to make a
free call to the same number over and over again.