h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Is it one movie about all 5 books in the trilogy or just the first? if it's only the first will they have movies for the other 4? Anyone know at all?

No-one's actually said that the books are the starting point for the movie. It might be closer to the original radio series, which was adapted into the first two books. Or it might be a brand new approach where the story is told in a different order - after all, this was Douglas's umpteenth script based on the same story, and each time he adapted it he changed it.

I loved the way the books were different from the radio series, and that the TV adaptation was different again. I seriously doubt the film is going to follow the same structure as any of them. That way it'll be something new for fans and newcomers alike.

But basically they plan to make more than one movie, don’t they?

That is, in my opinion, one disadvantage of the new radio series (tertiary phase and following). They try to stay true to the books, but it is difficult (and sometimes impossible) to "convert" written humour to spoken humour.
I think the old series was much more funny. Just replay episode 7 and compare it to the new episodes, then you'll know what I mean.

MedO