OK, Google started the service to send free SMS’s to US cell phones, but they haven’t yet extended the service for Canadian Cell phones. But each of these Canadian cell phone service providers provide their own service to send free SMS’s to their customers.
Here is a compliation of the various sites from where you can send free SMS’s to Canadian Cell phone users. You just need to know the phone number of the person you want to send the SMS to and their cell phone provider.
Bell Mobility Free SMS Service:
http://www.txt.bellmobility.ca/
Offers free short message service from the Internet to Bell Mobility mobiles.
Fido Free SMS Service:
http://www.fido.ca/
Service is able to send free SMS to GSM mobile phones in Fido coverage zones. It seems to also work with Rogers Wireless.
Rogers Wireless Free SMS
http://www.rogers.com/
Rogers Wireless High-Speed text messaging service gives you the ability to send free text messages via the Internet for free.
Telus Mobility Free SMS
http://www.telusmobility.com/
Send free sms via the Internet to any Telus Mobility telephone anywhere in Canada
Gagan's Blog (www.Gagan.ca) 
A VERY USEFUL SERVICE PROVIDED ONE IS SUPPLIED RELEVANT PHONE NUMBERS OF THE SERVICE PROVIDERS.IT CAN BE IMPLEMENTED BY THEIR COUNTER-PARTS IN OTHER COUNTRIES AS WELL.