While Google Calendar SMS notification seems to work for many locations, does it work for Canada? Reference: http://cantada.ca/
The option seems grayed out:
However, Google seems to indicate that it's possible:
Canada
Aliant Bell Mobility Fido Microcell Telecommunications Inc. (Fido) MTS Mobility NorthernTel Rogers SaskTel Mobility TBAY Mobility Telebec Telus Mobility Virgin Mobile