Historically, McGill has accepted a greater
percentage of international applicants than out of province Canadians. You can see the stats here
http://www.afmc.ca/pdf/2009AdBk.pdf on page 24. However, the number of spots for international (9) and out of province students (8) is about the same (at least it is this year), with approximately 8 of each (see website
http://www.mcgill.ca/medicine/admissions/criteria/selection/). I think the discrepancy is because more OOP Canadians apply than do international students, but this is just speculation.
Obviously the most spots at McGill are reserved for residents of Quebec, so if you're dead set on McGill you might try to gain status there. I'm not sure how it's done, but I think it involves living (and working?) in the province for some period of time without being a student there.
If you have your heart set on McGill, I encourage you to apply. After seeing what people said about how hard it is to apply as an OOP I almost didn't bother, but then I ended up getting in! If you are a competitive applicant (I'd say 3.8+, 30+) you should have a good chance at getting an interview, and whether or not you are offered a spot is then highly dependent on your interview performance. Also, I would definitely check out the Canadian version of this site (
http://www.premed101.com/forums/index.php) because there's a whole section for questions about McGill and there will be many more people who are knowledgeable about applying there and getting in.
One more thing- If you don't speak any French, I suggest you start learning. Not only will it potentially help with your application (it probably helped mine), but it will help you once you're living in Quebec.
PM me if you have any specific questions and good luck!