Since there are no pre-reqs for the MCAT, don't take a course just because you think it'll be good for the MCAT/getting into med school. Take courses you're genuinely interested in-you'll do better and enjoy it more. That said, check out the MCAT prep books-if you can't afford to buy one (they are rather expensive), just flip through one at Chapters to give yourself an idea of what's on the MCAT. You're asked basic biology, chemisty and physics questions-although some of the questions can be a little tricky!
To get into med school you should focus on two things: Getting the highest GPA you can (taking whatever classes you want-just make sure you cover any pre-reqs for the med schools you want to apply to-check OUAC for a complete list, but generally it's wise to take a full years worth of chemistry with a lab (preferably organic), a full year of biology with a lab, an essay course (like English, history, etc), and some sort of physics course) and getting as involved as you can in whatever interests you (clubs, volunteering, sports, etc).
You can get research experience in your upper years, but start trying early. I started as a volunteer with my one biology prof in the summer after my first year. Just keep your eyes and ears open-a lot of times profs will announce research openings for undergrad students. You can always try emailing your prof or talking to them about helping them out with research, and check your schools job postings in the summer because a lot of paid (and volunteer) research opportunities will come up around that time.
4th Year Mac Science Student.
Mac Psych Society Executive Member 2008/2009
Mac Community Standards Assistant 2008/2009
Vote for me:
http://www.cbc.ca/nextprimeminister/candidates/shilodavis.html