TS|Freelancer writes (contains spoilers):

On Sunday night I watched an exclusive clip of the complete General on the bridge of the Invisible Hand! It was the completed shot which will be seen in the movie and it's the first time we can see Grievous in a close up and he's moving. There was the shot of a ship landing on a landing bay on Utapau which can be Grievous or Obi Wan. All clips are German only clips because the show Focus TV on Pro 7 got one of the animators (who is german). There were also some shots of The Duel and the escape of Bail Organa. They were awesome!

You can discuss and download the clip in this Jedi Council forum thread. Please note, the discussion does contain spoilers.

Update:
Here's another description from Billy_Dee_Binks:

First we got the see a shuttle (looking like a Neimodian one) flying down into a sinkhole landing in a docking bay area. The design of the Sinkhole places is very similar to the unused concept of TPM's Tatooine cities. The ground around the area was very yellowish and looked squishy but the inside was rock walls- very dark ones with whiteish houses and buildings attached.
The landing area/ hangar looked like a grey circus tent with metal strings. It was a long approaching shot and then another
landing one.

Then Grievous got shown, entering the bridge of his battleship, the Invisible Hand. He looked amazing. It was very up close as the doors open with shadow stripes running across his mask. Then the camera pans back and shows the whole bridge (which was all digital by the way). Now, HIS WALK was really interesting. He walks like a vulture. It is very obvious and it fits him perfectly. I must admit, it looks slightly goofy but then again you feel his menacing character, and with the sounds added it will feel more imposing. He is very unique, believe me.

After that we got a new glimpse of Skywalker Ranch with Matthew Wood telling us all about the sound. A frame of the title scroll was seen (in which GENERAL GRIEVOUS is written). Then he talked about how to give the Battle of Coruscant atmosphere.

First he showed some brand new footage of what I believe was part of the long opening shot. The Jedi Starfighters sound like RC cars, pretty speedy, IMO. Then other footage of the space battle with music added. Then Anakin talking to Obi Wan while flying around, each in their own fighter asking which ship could be Grievous. Anakin then mentions the one ship that is covered with Vulture Droids. The interesting thing was how these droids sounded as soon as they detected them. Like a mixutre of Pit Droids/ and birds and something else.

You can also read more at Darth-Sonic.de here and here.