This device - and many like it - has been available in the United States for a long time, but now it has come to Canada. I got one from the Play store as soon as I saw it announced. It arrived yesterday by UPS.
While most pictures just show you what looks like a fat thumb drive, you need to know that it plugs in to the HDMI port - and has a neat little short cord if it is too chunky to plug directly into your tv. Some older models seem to delight in hiding their input ports. It also has to be plugged in to a power source.
Basically all you have to do is plug it in and switch the input. Again, older tvs tend to have just one HDMI input so I have to manually switch cables between the Apple TV, Telus Optik device and the Chromecast. I use my Nexus 7 tablet with the free app on the play store. There is no need for a remote control - but you could also use a laptop (I have put the cast extension on the Chrome browser on my MacBook too) or phone. And I have tried it out on more than one tv without any issue.
Then get some content from the internet. Start with Youtube. The app on the tablet has suggestions for other apps that are Chrome cast compliant. Apparently it is also possible to use it to put anything from the screen of your laptop on the tv. I have not tried that yet - and it is something I feel I ought to be able to do with Apple TV but cannot because my MacBook is too old.
It also works just as easily with my partner's iPad. You get the chromecast and YouTube apps from the App store. Free.
Very odd that one of the trial programs my new YouTube app offered me as a test was an old tv program at low resolution. Very unimpressive but there is plenty of free HD video out there and mine just works fine. When I bought the (Nexus 7) tablet I got "Transformers 2" for free: it is not the sort of movie I usually watch, but I played enough of it through Chromecast to be be impressed by the special effects. Odd that the Google Play store leaves up the old user reviews of people with M$ operating systems who had trouble back in the days when it was still new and all.
I do not understand why some people are suggesting waiting for Roku. I wouldn't, if I were you.