The Official Site has announced that Darth Vader and members of the 501st Legion will be onhand at the Consumer Electronics Show in Las Vegas this Thursday at the Panasonic Booth(#9408).
The announcement will be made at 11:30 AM PST/ 2:30 PM EST.
Most common speculation has that it will have something to do with either the Star Wars 3D release or the Blu Ray release. Though Dunc at Club Jade has an interesting thought that it might be related to Panasonic's new handheld gaming device dubbed "The Jungle," and could be tied into the ability to play Star Wars: The Old Republic MMORPG on the mobile device.
My guess is that it is to announce some sort of exclusivity or bundling deal with the Blu Ray release and Samsung Blu Ray players or Televisions. We will all find out Thursday.
During Celebration V (CV) George Lucas and Lucasfilm has announced that both Star Wars Trilogies will be released on Blu Ray in Fall 2011, without yet giving a release date. Official Announcement Link
Lucasfilm has also previously announced that all six movies will be re-processed and re-released theatrically in 3D, starting with Episode I: The Phantom Menace in 2012. Official Announcement Link
ILM's John Knoll talking about sterio-conversion of Star Wars into 3D. Video Link