Kotaku are reporting that LucasArts are planning on making "several world exclusive announcements" at this year's Comic-Con in San Diego, next Friday. Since they're planning the announcements for the Star Wars Spectacular keynote address, I'd expect them to be related to that franchise.
Personally I'm betting on Star Wars Battlefront III, although if Imperial Commando turns up it'll blow my mind. Force Unleashed II is also a possibility.
They'll also be showing off Krome's Clone Wars: Republic Heroes, TT Games' Lego Indiana Jones II and Bioware's The Old Republic.
UPDATE: Apparently The Force Unleashed's just had some new mysterious achievements added, making it look like one of the announcements could be another downloadable map for the game in the form of Jabba's Palace.