Canada is slowly coming back in terms of a hardcore following. Most of the up and coming bands are in and around Toronto and Ottawa. Here's a list of bands around here...
Shut Eyes (Barrie)
Desperate Times (Niagara Falls area)
The Author (Niagara Falls)
Think Twice (Ottawa)
I'm from Ottawa - just over the bridge from Quebec/4 hours northeast of Toronto.
There's been a bit of an uprising in hardcore with a younger crowd in Ottawa for about a year or two now, which most people attribute to 3 new bands that emerged around the same time, and how they've opened up hardcore to a lot of people who identify themselves as "metalcore" listeners. The three bands are Substance, Think Twice, and Constraints.
Ottawa has actually started a facebook community called Ottawa Hardcore which promotes shows and local bands and updates people on what's going on in hardcore, metal, and punk (we were gonna get OHC windbreakers at one point haha).
I'm of course not even coming close to skimming the surface of what's going on. I'm not trying to toot my own horn saying that my band is one of the bands that brought back hardcore in Ottawa, it just seems like no one from the younger crowd followed it closely until us, Substance, and Think Twice popped up around the same time.
There aren't really any zines that I know of but you could check...
There's Finish What You Started Records, which is run by a guy named Ska Jeff, who has put more work into the hardcore and punk scenes than anyone could possibly ask for.
Venues: Kent St. House, Maverick's, Cafe dekcuf, Babylon, Ritual, Kent St. Legion
Promoters: Ska Jeff, Shawn Scallen (company is called Spectrasonic, they book everything from hip hop to metal to indie to hardcore)