The Ultimate Sacrifice scene that I refer to has Clark returning to the Fortress of Solitude after learning about Zod et al. taking over earth. When Clark (or, perhaps Kal-El is appropriate at this point) calls out to his Father, Jor-El appears, and after a brief conversation, he says that he anticipated this move from Kal-El and planned for it, but the result would be that he could no longer appear to him. Then using some form of energy emanating from his eyes, he zaps Kal-El, fade to white, cut to Metropolis where Zod et al. decend upon the Daily Planet. Big rush of wind, Superman is back and the fight in Metropolis ensues.
The common folk don't know if this was filmed and pulled per the Brando suit, or if it never got filmed. It could certainly be recreated in CG, but what would the point of that really be? But we do know that Brando filmed something intended for Superman II that has yet to see the light of day in any version of the movie. The Brando family has agreed that Bryan Singer can use this in Superman Returns ... and this is the one shred of news that has really excited me about the film. Anthony Hopkins would certainly have been a cool Jor-El, but actually seeing Brando rise from the grave and have his own footage incorporated is promising.