NSCAD (Nova Scotia College of Art and Design) is a great school. I'm finishing my undergrad degree there this year, and it's been a really great experience. I should mention though that they're currently going through some rough financial times - although I think this impacts undergrad course offerings much more than grad students. It's a really great school though - and quite small. I think they take something like 8 grad students per year. The faculty are great - really engaged, and they're always around.
OCAD (Ontario College of Art and Design) is the biggest art school in Canada. I don't know much about it's grad program except that it's relatively new (been around for 5+ years?). But in general the school has a good reputation. It's in (downtown) Toronto, which has a really great, thriving arts scene.
Emily Carr (in Vancouver)
University of Toronto
University of Alberta
York University has great facilities and funding, but is in the no man's land that surrounds Toronto, and I would hate for it to be your introduction to Canada...
Concordia - in Montreal, which is a fabulous city, with a great arts scene
Western (in London), and Guelph might also be good to check out
There's not that much info about Canadian schools rankings, especially for arts schools, but McLean's magazine does a yearly run-down of all Canadian Universities (all of the above are degree granting universities), and Canadian Art magazine does a similar thing for Canadian art schools (although I don't know if it's annual).
Also, although I don't know what funding is like, Canadian schools are significantly cheaper (even when you're paying international rates).