On Saturday we received the disc from Netflix that enables instant streaming on the Wii.
This gave me a good excuse to plug the Wii back in, as I hadn't gotten around to it since we moved house.
The set up procedure is very nice. You put in the disc, start the "game", and it spits out a code. You go to http://www.netflix.com/Wii and enter the code. I imagine it looks for a request from the Wii with that code, and an authenticated submission with the same code from a web browser, within a certain period of time, and puts two and two together. It beats having to enter your username and password for your Netflix account on the Wii.
The UI is very nice. You get a horizontal list of the titles in your Watch Instantly queue, and you just pick what you want to watch, and away you go. The video quality seemed fine.
We'll definitely be watching more stuff from our Watch Instantly queue now.
Full disclosure: I am a Netflix shareholder