Unpaid internships are illegal in Canada, by the way, so you'd have to be hiring/getting help from someone out of the country.
edit: added link to Brock. He is awesome BTW, highly recommended.
http://blogs.hrhero.com/northernexposure/2009/06/15/beware-t...
You have to just be careful while your doing it same as when you hire someone as a contracter making sure you don't treat them like an employee.