There's a community I belong to that I get the current episodes of TV series from and they'll definitely have Korra. I'm going to have to do the same as you since I don't have cable either (if Nickelodeon doesn't stream them.) So, if they're not on iTunes, I can either give your my LJ access to get to the episodes (I do trust you. ^_^) or download them myself and pass them to you through AIM or my Dropbox.

And, yes, you can get all of the current episodes of Futurama at least on the American version of iTunes.