The following was scanned from the "Canadian Flight Supplement" and may not be completely up to date when you read this.
There is no substitute for up to date information, use current charts when visiting unfamiliar airports.
For U.S. aircraft coming into Canada, file a flight plan, then phone Canada Customs at 1-888-CANPASS (1-888-226-7277) at least 1 hour prior to landing in Canada.