Well, this is interesting. I recently went into the Android Market on my Galaxy Tab and it asked me to accept the terms and conditions again. I accepted, and the app closed down. When I booted the market back up I had a shiny new "movies" tab. In my preview of the Touchwiz UX update, I noted that the update came with the "Google Videos" app pre-installed but that the market didn't have movies available for purchase yet.
One puzzling thing is that the playback worked flawlessly on my rooted galaxy tab, but Josh's rooted phone just gave him the playback error we all know and love. My device is running essentially a "stock" Touchwiz build, so that might have something to do with it.
Like most market updates, expect this rollout to go out gradually, but it can't hurt to clear the cache to try and force and update. One additional screen capture, and a blurrycam pic of actual playback (since the videos app seems to block screen capture methods) after the break. If you get it on your device, be sure to sound off in our forums.