The news of an add-on called (or by?) Understudy can easily be read elsewhere, but I wanted to add my thoughts since I didn't see too many others talking about using it.
First of all, it's not a full Netflix wrapper like those on a TiVo or Xbox 360 or Boxee. But I think it's a simple, clean way of getting access to your online queue.
In order to use it, you have to be logged into Netflix's site through Safari, since Understudy will pull your RSS feed data. Then, you can view and play your content like you would any other content in Front Row. You don't have access to edit your queue or anything like that though. It's just a viewer.
Once your content starts playing, it's pretty much full screen. There's a button for Full Screen play, but I didn't seem to have any mouse access to select it. I think it may just be there as part of the normal browser-based player that's getting crammed into Front Row. ???
Regardless, after 5 minutes of playing with it, I think I'll use this as my way of watching content on my Mac. I tried Boxee, but I don't like the fact that I can't get the Apple Remote to control the system volume in Boxee. The remote wants to control Boxee's volume, which on my system, results in the same output volume to my speakers regardless of the app's volume setting. So it's pretty much useless. With Understudy, since I'm in Front Row, I have full access to all of the normal Front Row functionality, including system volume.