NAFTA has some exceptions for software-type jobs, but there is a requirement of 2+ years of experience. I looked into this like 6 years ago, though. I don't know what the situation now is. Some companies are not too keen on treading the work visa waters though.

Thanks, I ask because in terms of geography and distance, it's an order of magnitude different than, say, a programmer coming to the US on an HB-1 or an American going to the UK. It seems like they could get some decent American programmers without the new hires having to move too far. But probably not without visa help, right?

If you have enough qualification points, and sometimes subject to a province's discretion, you can get a Canadian work permit without being sponsored, which can make it much easier to subsequently find jobs. From what I hear, applying directly to Alberta or Quebec via their provincial-level immigration offices is the best bet (with the latter it helps if you can say you know at least basic French).