The Canadian Airgun Forum has tons of great info & people. - 06-11-23 Well, *some* people, heh. Apparently I'm a troll, so I've been banned, haha. Gotta love immature forums admins. You'll find a lot of good info there, just don't disagree with anyone over even the smallest little thing, or you'll be out on your ear! haha
The Crosman Airgun Forum is a pain in the ass to use and navigate, but none the less is a pretty big place with a lot of good info, too. Sure would be nice if they switched to some sane forums package. Naturally it is mainly concerned with Crosman airguns. They're home to a lot of Crosman mods.
The CZ forums don't seem to get a lot of traffic, at least not in the airgun section. Worth checking out, and they've got rimfire/centerfire sections, too.
Target Shooting Canada has a bunch of good content on airgun sports. They've also got an online postal match in the various disciplines. Anyone can shoot a match at home, or wherever, and submit your score to see how you did against others doing the same. My pitiful scores start in the August 2006 match, in the 10m air rifle 60 shots section.