One of the most frequent questions law students ask about legal research is whether the "McGill Guide" is online. Of course it is not. There is, however, an online "American" citation guide – Peter W. Martin's Introduction to Basic Legal Citation at http://www.law.cornell.edu/citation/- but this does not have Canadian content.
In checking out Wikipedia on various legal research related topics, I see that they have a good article entitled "Case Citation" at http://en.wikipedia.org/wiki/Court_citation which, although emphasizing US case citation, does provide examples of Canadian, British, Australian and NZ case citations. Unfortunately, there is a comma missing in the first Canadian case citation example to the Big M Drug Mart case . . . .