Visa info needed for Unpaid internships

HI,
I have been on so many sites and called so many numbers and seem to remain in the same spot. Hopefully someone can point me in the right direction.
I am canadian, an undergrad student, doing an internship (unpaid) in NYC this summer. I am doing this internship on my own, it is not through my school.

I have no idea where/how I get a visa for this.
I am also wondering if this will allow me to work legally there? And if not - is there a way to apply for that?
Also - how long does this process take? Im meant to start mid - May - I would have started the process sooner, but didnt think I would get a reply so soon!!

I may take on another internship that might be paid - is this a different process then?

Thank you so much for any information!

SWAP is the usual way of doing this: http://www.swap.ca/out_eng/destinations/usa_summer.aspx

Failing that, the employer themselves can sponsor you, but usually they need to be State Dept. registered which means they're some sort of accredited educational facility, so you can get something like J-1 or M-1 status.

Or depending on what the job is, they might be able to sponsor you for H-3 which doesn't require them to be registered but it does require them to file an I-129 for you, I doubt it would be approved by May.

Have a poke around on the USCIS website for the definitions of J-1, M-1 and H-3.