It varies from province to province, depending on each jurisdiction's Motor Vehicles Act. In BC they're legal, in Alberta they're not (or vice-versa, maybe? Don't quote me in court, 'cause there's a good chance I've got it backwards). I'm pretty sure radar jammers are illegal in all provinces, but not detectors.
The detectors are illegal in Mannitoba, that's all I know.
Hey Thinker, just don't try flashing your brights six times with any cops around.