There are many opportunities for Canadians to win great prizes from US and international contests. However, there are also excellent sites that serve as directories for sweepstakes specifically geared for Canadian citizens. Below are a few of the most popular. BellaOnline requires that I limit clickable links in articles, so I've placed the URLs next to the site names.
Contest Canada.com (http://www.contestcanada.com/in-portal/): This is not a free site and registration is required. However, you don't need to enter your credit card info for the 30-day free intro trial. After that, membership costs $25 a year. The description on their membership page states that they offer an "extensive list of Canadian Only Online & Snailmail Contests." No US or international sweeps are listed. An email newsletter is available to keep you up-to-date, as well as a member forum.
Contest Canada.net (http://www.contestcanada.net/): This is a listing site. Each contest listing links to the specific sweepstakes. The site is well categorized and you can easily find the type of sweepstake you're looking for on the sidebar. There are several forums including a general discussion board, winners list and tips and tricks for winning. Contests for cash, gift cards, trips, kitchen and electronic items and much more. Email updates are available. You can also suggest contests for the site as you come across them on your own.
Somewhere in Canada (http://www.somewhereincanada.com/): A community driven site where visitors can enter contests. Membership isn't required but signing up for a free account will enable you to comment on postings and contact other members. They also have a specific section for contests that are valid in Quebec. Some prizes offered include cash, gift cards, clothing & shoes, electonrics and trips.
Sweepstakes.CA (http://www.sweepstakes.ca/): Free membership. You do need to fill out a registration form with your name, address, email and phone number. Enter contests to win cash prizes, trips and more. Some offers are interactive where you need to play games or sign up for promotional offers in order to enter a sweepstakes.
Most of these sites have a Facebook presence and many of the sweepstakes offer Facebook entry options. Another great site is Royal Draw which I've reviewed here. Good luck to all Canadian readers.