As Scylla say it is very difficult to secure a job from outside Canada given as you can imagine there are thousands of people wanting to make the move and if companies replied to every speculative CV or everyone that said they are planning to come but never turn up they would never fill any positions wasting so much time.
Many people come over on a vacation, send out some resumes in advance or even simply turn up at the bigger companies and do a lot of networking just so that employers actually see a person although rarely unless someone has some unique skills not readily available in Canada would any employer for example sponsor anyone, would need to be really unique in IT for example. Networking employers is the key but until someone is a landed PR actually even getting interviews even via Skype is not impossible but unlikely.