OMG stay away from commercial physician recruiters (unless you have neither Royal College nor American board certification). Waste of air talking to them.
Start here:
CMAJ classifieds
Your medical specialty national website classifieds e.g. if you're a pediatrician it's the
Canadian Society of Pediatrics and so forth
http://www.healthforceontario.ca/ (all the other provinces have similar websites)
Your medical specialty big American/international journal "jobs section" e.g. if you're a pediatrician it's the
American Association of Pedatrics Journal
Even the
CMA has a job search function
If you want to work in Ontario AND you have your Royal College certification, it'll be a breeze - just go straight to the Health Force Ontario people and they'll have a half dozen possibilities lined up by the end of the week (I'm a final year resident who passed my RC and I did just this - talked to HFO - and I was ASTOUNDED by how many jobs they scrounged up in 24 hours). Even if you don't meet the requirements, they can probably help you figure out what's missing from your CV and might have suggestions for fixing it.