Try adjusting the Motion Judder Control in the Picture Options menu.
Menu > Picture > Picture Options > Motion Judder Canceller.
Also, in the Picture Options menu, there is a Film Mode and Cinema Smooth option, however a 1080p (24Hz) signal must be used to adjust the Cinema Smooth function.
Keep me posted on which one seems to work best for you.
I just purchased a PN58C8000 and 3D Blu Ray. The movies on Blu Ray look awful, they look like soap operas much too clean and crisp the flesh colours are not that great. Anything cartoon is OK but movies look like they have been filmed on video and not film. Is there any way I can change this other than hooking up my old DVD player to look more like a rich movie filmed in film other as opposed to glossy soap opera made on video? I tried changing it to 1080P with 24 HZ instead of 60 HZ but it still looked awful. TV looks fabulous but Blu Ray movies and DVDs played in 2D look cheap.