What you need to live/work in Canada as a postdoc:
Surprisingly, not too much. If you're in Canada less than three years, then you are a temporary resident. If you are coming from the U.S., you don't even need a temporary resident visa (for info on what countries do/don't require visas, see here). You also don't need to import your car, though you can obtain provincial plates. I will probably change mine to Ontario.
The work permit:
Here's the biggie. You need to apply for a Canadian work permit before you go to Canada. You can apply from within the country, but you'll have to go to a border crossing to get your actual work permit. Here's the kicker: you don't get the actual work permit until you cross the border. You apply for it beforehand when you are still in the U.S., and then after your approval, they send you a letter to give to the officials at the port of entry, and they issue your permit. The list of what you need to apply is a bit extensive, though, and includes:
-Your offer letter. You are dead in the water without this. Get it ASAP. Be sure it says how much you will be making. **IMPORTANT** Make sure it also states that your postdoctoral position does not require a code from Human Resources and Skills Development Canada stating that you will have a positive impact on Canada. Postdocs are exempt from this. A university letter should already have that in its template, because this happens a lot.
-A copy of your passport. A passport has been required to enter Canada for a while now, so this shouldn't come as any surprise.
-Two photos of yourself, taken to Canadian specifications. Don't forget to not smile!
-$150. Processing fee. Personal checks not accepted; get a money order.
-The form "Applying for a Work Permit Outside of Canada". It will require things such as your passport number and expiration date, so keep the passport handy!
-A place to send everything. A list of all available offices in the U.S. is available here. I chose the Buffalo office, because I am close to it geographically, and I figured it handled a lot of these things.
-Proof of a Ph.D. This was a toughie for me because... I don't officially have one yet and won't until May! Commonly, doctorate-granting universities will issue a letter stating you have fulfilled all requirements as approved by a Dean upon request; however, this can take a while to get, so hop on it quickly. I did not have this letter, so I submitted both my CV and a letter from my advisor on official Penn State letterhead. My advisor's letter stated a brief summary of my duties, said I was done with requirements, and gave my defense date/salary. They accepted it.
You get all of this together, and mail it to your chosen office, and then.... you wait. And you don't hear anything. You cannot contact them unless you've waited an inordinate amount of time (i.e., 3 months). You just sit back and hope. I believe that if you are a Ph.D., they expedite the process. I mailed my documents on December 10th or thereabouts, and my approval letter is dated January 12th. Keep in mind that that span of time included Christmas Eve, Christmas, Boxing Day, and New Year's. This will not get approved overnight.
The itemized list o' stuff:
When you cross the border into Canada, they will require you to bring with you an itemized list of what you are bringing in. I have it on authority from 2 Canadian officials that they don't care if you itemize every single little thing, just a general list for a temporary resident. Also, you need to estimate a monetary value in $ CDN of each item in the listing. It's not too hard; I'm doing it as I'm packing, and the movers will itemize what is in my boxes, and I will estimate a monetary value of each box.
Surprising things you don't need to get into Canada: A birth certificate, social security card, or driver's license/gov't-issued ID. If bringing in a car, though, be prepared to have the title/registration/proof of insurance.
I am sure I will have more to report once I cross the border, but for now, it's back to taking stuff down off the walls and packing!