Well, the initial rumor about Galactus in the movie was that he was a big gay space cloud, but now I'm hearing that he is a cloud and that he's not, all from people who have seen the movie, so it's obvious some people are full of shit or lying.
If you watch this trailer on Youtube though, 21 seconds into it you see a shadow moving across a planet that looks a LOT like Galactus's big silly helmet.
http://www.youtube.com/watch?v=2K2Ydf0V7RY
So who the hell knows, really. I just hope he's not a big gay space cloud. At least a big purple guy will give me something to laugh at.