Netflix is rolling out a major update to its Xbox 360 application today, which is the biggest update to arrive since the integration of Kinect gestures and voice control back in December of last year. The updated app brings a number of new features and enhancements, but the most notable changes involve improvements to Facebook sharing in select markets and single sign-on support using your Xbox LIVE credentials. Single sign-on means you can now sign using your own Xbox LIVE account in order to watch Netflix movies on consoles other than your own.

Also included in the app’s refresh are improvements to the Skip Forward and Skip back buttons, a zoom function that lets you enlarge letterboxed video to full screen mode, and better contrast, which Netflix says will make colors more vivid and blacks more pure.

For international users, Netflix has improved Facebook integration for members in Canada, Latin America, the U.K or Ireland. This allows Netflix users to see what shows their friends have watched and rated on Netflix. Users also have more control over what shows and movies they’ve viewed when sharing to Facebook. Unfortunately, these social features are not available in the U.S. at this time due to legal issues surrounding the 1988 Video Privacy Protection Act, which prevents users’ movie rental activity from being shared.

Changes to that act have been making their way through Congress, however, which could allow Netflix to include the social sharing options within its Xbox 360 app in the U.S., as well as offer an Open Graph-enabled application on Facebook itself.

As for now, current Netflix users will automatically receive the updated the next time they go to launch the app on their gaming console. New users can download the app from the Xbox LIVE Apps Marketplace instead.

Update: We’ve reached out to Netflix for more details on how the Facebook sharing options have been improved.

Update #2: A Netflix spokesperson has clarified the social sharing changes for us, stating:

“Indeed, we have had Facebook integration in these markets, but we have now expanded that on Xbox. Specifically, members who use Xbox 360 with Netflix will see additional rows in their Xbox experience that show what their friends watched and rated so they can discover new things to watch. We have also added more granular sharing controls so members can decide not to share on a title by title basis.”