It looks like our American friends can now call Canada for free via Google Voice, and this is in addition to making free long distance calls within the US, reports googlevoiceblog.
The offer was originally offered in GandCentral, and now to bring as many features as they can for free they are bringing free calls to Canada with Google Voice.
Apparently calls can be initiated from the new mobile application, from your inbox online, or by dialling your Google Voice number from one of your phones and selecting option 2.