To get a Special Occasion Liqour License you have to apply to your local Alcohol & Gaming Authority or pick up an application at a licensed liquor store and download the application on-line. The applications vary from province to province. The license is only about $10. Having your own license allows you to purchase your own bar supplies or have your caterer purchase them for you. You may like to charge for drinks which is a great way to recup wedding expenses.
If you can coordinate things yourself or put one of your parents in charge of this, it is best to get your own licence and run your own bar. It is $75 for the Special Occasion Permit. This licence also allows you to serve homemade wine with dinner. We got ours done at PureBrew.ca on St-Joseph.