So you can buy South Park or... well, South Park. Ok that's a bit of an exaggeration, the networks they currently list are CBC, Comedy Central, CTV and the NHL. There are only one or two shows from each; there are a total of 14 different shows up, with at most two or three seasons of each show.
(Check out the trailer -- with rude bits of course - for "Make Love, Not Warcraft".)
Here's what the interface looks like:
Individual shows are C$2, entire seasons depend on the show, South Park is C$24, the Hills season 3 is C$36. It's a bit apples to oranges but the Hills season 2 DVDs are C$43 discounted at Amazon.ca
What rights will you have to content? Well Apple has its own ideas, but ultimately it will depend on Canadian copyright legislation. Currently the court interpretation of Canadian rights is pretty good, so of course, some organisations think that must be stopped.
It would be nice if we could get away from this idea of geographically negotiated content rights too - it is ridiculous that it takes months or years for content that is available in iTunes USA to become available in iTunes Canada, if it ever does. As it is, you can see that there are no US networks on iTunes Canada. In fact the whole concept of "US network" doesn't make much sense in the Internet world.