Yes, the Union representing Canada Post employees gave 72 hours notice, so they will be in a legal strike position at 11:59 PM Thurs...they have been negotiating for 7 months. (No I do not work for Canada Post or the Union). Now, they say that Government cheques will still be delivered.
Here's an article from today, from CBC news.
Just an example of postage shipping I recently experienced. I have done a few trades, and a kit for a kit cost the guy mailing via USPS to me in Canada was $5.94. The same shipment, a kit shipped by me to the guy in the US via Canada Post was $12.54. Just to add to it, the shipping time was about 12 days from Canada to the US, and from the US to Canada was about 14 days (not bad, on average, though I have had the odd shipment take 6 days, and others take 25 days!) The examples are for standard ground shipping, so longest, and cheapest. UPS, FedEx, Purolator or DHL are probably twice again. Too bad Greyhound doesn't do international shipping! I've sent some bulky 1:1 car parts for pretty reasonable within Ontario.
Hopefully, cooler heads will prevail, and they will avert a strike. No one wins in any strike I've been aware of.
Just keep an ear out if you do set up a trade with one of us up here!