Check with Canadian customs to make sure that whatever is being sent is acceptable - liquor, tobacco products and guns are obvious examples of items that are not permitted. A good place to start is the Web site of Canada Customs and Revenue (www.ccra-adrc.gc.ca).
Step2
Advise your Santa to write the words "gift" and "cadeau" (since Canada is officially bilingual) clearly and in large letters and to check the "gift/cadeau" box on the customs slip.
Step3
Keep an eye out for a notice that your package has arrived, especially if you're not home much during the day.
Tips & Warnings
If Santa makes a mistake, don't worry too much - just keep copies of everything and apply for a refund of whatever you got charged (usually, Government Services Tax or GST).