buliding a bilingual site is a topic which could go on for ever... it's just dang complicated. It seems like it should be simple but it just ain't.
Where I work now, we do it the smart way. Our templates are all language-agnostic, and we keep all our phrases in an enormous XML file as we develop the interface. That file is parsed, compiled, and cached in a dictionary object so it's always in memory thus assembling the layout is super-quick. Since all parts of the site are modular and programmatically rendered (with aggressive caching), it's simple to build any page, passing "en-us" as a parameter.
You need to figure out early how you're going to architect the bilingual site. Develop your URL strategy. My favourite method is to build "en.example.com" and "fr.example.com", and for every page on the "en" there is an identical (but translated) one on the "fr". "www" redirects to "en" by default, but may redirect to "fr" if the user has a french cookie.
I once worked for a company that insisted that not only should the content be bilingual, but every part of the URL should as well. That meant that there was a page called "health-insurance.html" but the french version was called "lassurance-maladie.html". That was a nightmare, I kid you not (it was a 2000+ page static website built in FRONTPAGE.)
What Leosghost says is true. Québecois is about as similar to Francais as US English is to UK English. It's mostly the same. But the differences will be very apparent to a Québecois reader. Imagine you're reading copy full of references to "trousers" (pants), "jumpers" (sweaters), and "chips" (fries)... you just know that the copy was written by a Brit. Make sure you have a Québecois translator do your French for the .ca site.
Interlink the english and french versions diligently. Let each french page have a link to the english version, and vice-versa.
Incidentally, bilingual sites tend to rank extremely well. They have a greater surface area for inbound links, and the interlinking form en->fr and fr->en passes PR efficiently from one language to the other to both sides' benefit.