Working in Canada as Contractor:Need help!

[IT applicant]

Hello All

I need to understand from someone the funda of working as an indep. contractor in Canada.
I have come across various openings wherein the placement agency is not running any payroll in Canada(and has an opening for a client in Canada)
In such cases,the placement agency will hire me as an indep contractor(and will not take me on it's rolls).What I need to check if I need to be incorporated as an organization in Canada to work in such kind of job

Please help based on your experience/research

cheers!