According to this, Lego Indiana Jones will have four-player co-op "on the console versions", and will hit the US on June 3, a week before the release of the new Indiana Jones film.
There's loads of other stuff through that link, including details on the whip system for Wii and why the only difference between the enemies in the game and the Nazis in the films is that "the bad guys just won’t wear swastikas... The plot will stay intact."
Xbox 360, PC, PS2, PS3, Wii, DS and PSP versions will all ship simultaneously. There's no release date for Europe as yet, but will be seen at GDC later this week.