For those who live outside of North America, this might be helpful, in case you ever need to call someone in USA or Canada...

http://callingamerica.com/

Works for all numbers in USA and Canada. Call from the internet, and if you do not register with them, you get 2 minutes of calling per session. If you register, you get 15 minutes of calling per session. Unlimited number of sessions per day.

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As described in an article in the Globe and Mail:

In trying times like these, every little bit helps, even if it's just saving the price of a phone call. CallingAmerica.com is a new ad-supported Web service that lets you make phone calls to any number in the United States (and Canada) from any computer with a Web browser and a broadband connection.

The service, which begins Thursday, requires you to view a short ad before you place the call. The audio is played through the browser, and the site uses your computer's microphone to transmit what you say.

There is a limit to the fun, however. Unregistered users can make calls of up to two minutes; registration – which is also free – gives you unlimited calls of up to 15 minutes. While it's not as versatile as other Internet calling services like Skype or Vonage, it is enough to make a few quick calls while on the road without racking up long-distance charges.

Most important, the service works domestically and all over the world. That means you can call the United States free from any cybercafe or Internet-enabled computer virtually anywhere. While it might not be as cozy as a call from a phone booth in London, the service is certainly cheaper.

http://www.theglobeandmail.com/servlet/story/RTGAM.20081218.wgtgeek1218/BNStory/PersonalTech/home