If you want to immigrate to Canada, anywhere but Quebec, all the info is here:
Immigrating to Canada: Skilled workers and professionals
If you intend to Immigrate to the province of Quebec, see here:
Skilled workers and professionals: Quebec-selected skilled workers
If you do not want to go through the process on your own and prefer to hire an immigration consultant to walk you through it, he has to be licenced by Immigration Canada to act on your behalf. The licenced immigration consultants are listed here:
Find an immigration consultant
Good luck. Its a great country.