Netflix demonstrated a Microsoft Silverlight version of the Instant Watching movie player at the Mix '07 Confererence in Las Vegas. Looking very much like a DVD interface, the demo featured ratings (while watching), chapters, movie information, co-watching, and Macintosh and Firefox compatability.
Here's a video of the demo by Netflix's Neil Hunt and Darin Brown of Avenue A/Razorfish (via Webware):
Microsoft has posted a higher quality version on Visit Mix.
Tidbits: The demo was developed in less than 3 weeks, and Netflix customers have watched more than 2 million movies online.
Thanks to Greg, Calin and Christopher for sending this in.