Dear All,
Unfortunately most recruiters do not pay any attention to candidates who are not physically in Canada already as well as do not have a permit to work in Canada at the time they apply for jobs. Reason why is very simple, most Canadian employers look for candidates to start asap and who are able to interview also in person. If it is a very special skill, they might do look at candidates outside of Canada.
Especially IT is a very fast pace business, employers mostly do not have the time to wait until a candidate will be here and gets his permits.
Therefore I recommend to all newcomers, visit right away after you landed in Canada several agencies and let them know you are here.
Anyway it is always worth a try and apply in advance, but don't expect to much.
Hope this helps.