If you're still wondering how well the optical stabilization works on the Nokia Lumia 920 Windows Phone, we ran across a video using the Lumia 920 as an action cam over in the Windows Phone Central Forums.
According to the discussion, Windows Phone Central reader Allen Balkema strapped his Lumia 920 to his helmet and took it out for a spin through the woods on his four-wheeler. While the helmet mount didn't place the Lumia 920 at the best angle, you can tell from the video that the optical stabilization worked nicely.
Balkema feels that the Lumia 920's video performance was smoother than what he's seen from the GoPro HD Hero 2 action camera. You can catch the full fourteen minute video in this WPCentral.com Forums discussion.
Thanks, Allen, for sharing!