What is interesting to me about this story in the first place, is the how small the "Last Battle" really was. To begin with it only consisted of about 20 Nanians against 30 Calormens. In the very end it was more like 15 Narnians against hundreds of Calormens. I have a feeling that they will want to make the numbers greater especially since it is kind of the grand fen-ally. I can't think of other changes/embellishments at the moment. I will think it over and post more later.

The battle will most certainly be the highlight of the movie! I wonder how they will start off the movie, since the book starts off with brand new characters. That might lose interest since the viewers have nothing with which to associate them. I think this movie will end up PG-13 because of the violence of the battle and the hideousness of Tash (combined w/ the theatrical elements).

Hmm...I thought that Walden Media has an agreement to keep all the films PG (even though I don't have much against LB being PG-13). But in any case, I think Watziznehm may well be right --- the Last Battle will be a lot more epic! (Otherwise it would be such a letdown from the battles like in LWW and PC in my opinion.)

In any case, other than that...I think the filmmakers may change just how Eustace and Jill get into Narnia. You know how they made PC more oriented around the Pevensies then Caspian? I think they may make Jill and Eustace more of the main characters than Tirian. And as I kinda hinted a minute ago, the time-line is confusing at first so the filmmakers may try to clarify that.

Other stuff? I can't really think of anything much right now but I bet any confusing characters will have their personalities flushed out more. (F.e., Puzzle, perhaps.)

I'm nearly done reading LB as we speak. I think all the main parts of the book will be kept and unchanged in the movie.
I could see them adding more to LB then taking away or changing scenes.
And like everyone else is saying the battle at the end I think needs to be bigger, it needs to really show that this is the Last stand for Narnia, that their fighting for all that is worth fighting for in Narnia, for the Truth, for Aslan.

I could even maybe see them adding in scenes of other Narnian's joining Tirian, Eustace, Jill, Jewel, and Puzzle. Not just Poggin and Farsight (though they should still be considered main characters).

Or maybe instead of Farsight telling the group what had happened at Cair Paravel Tirian and Jewel go and fight the Calormene at Cair Paravel and then retreat with whatever Narnian’s that are left from the fight.
I think they could add the most new stuff from where Tirian meets Eustace and Jill, to when they actual go to fight the Last Battle.

And I think that the main message that should be kept though out the movie is Faith, and to fight for the Truth no matter what the odds.

Making the actual last battle more EPIC would ruin, imo. In the book, there are only a few Narnians and we've gotten to know most of them. We're emotionally invested in them. Huge armies squaring off against each other tends to be fairly impersonal.

right bookwyrm, the armies are relatively small as Watziznehm pointed out, but the number of Caloremenes increase over time... the battle still must be epic IT'S THE LAST BATTLE FOR PETE'S SAKE !! Anyway, I hope they develop Puzzles character a bit more. Do you think when jill goes to rescue puzzle and Tirian goes to rescue Jewel that there will be any, uh, killing? Any minor battles there?

The one thing I'm afraid they'll toss is most of the last chapters of the book in the real Narnia. I'm hoping they won't take it out, but someone will probably object to Aslan's country.
I think they will embellish the battle. I don't think it needs a whole lot, 20 Narnians attacking hundreds of Calormenes would be epic enough for me. But that will probably become rather grand scale.
One thought I had for entering the stable during the battle:
Eustace gets thrown in. He lands on the floor out of breath. The screen fills with white light. Cut back to the battle.
When Jill gets thrown in: She lands on the floor. The same white light shines, but just before cutting back to the battle, we catch a glimpse of a blue sky overhead.
And then when Tirian gets thrown in after Peter sends Tash away we can see the sky, the grass, the trees, and the kings and queens.

Do you think when jill goes to rescue puzzle and Tirian goes to rescue Jewel that there will be any, uh, killing? Any minor battles there?

I don't know. It's certainly a possibility. I think it would be better to be more of a cloak-and-dagger sort of thing than a skirmish, but that could be just me.

I like your stable idea, daughter of the King! That sounds pretty cool! I really hope they keep Aslan's Country and the real Narnia. That's pretty much the whole point of the series is one day living w/ Aslan forever. I can't wait to see the reunion in the garden! We'll see so many old friends! like puddleglum, tumnus, and the beavers!!!!

Oh I don't think they will cut out the "Real Narnia". As worldly as these film makers are it is a fantasy film that they are making here and will treat it as such. In the LOTR they didn't cut out Frodo going off in the boat to eternity so to speak just because that was too close to Christian doctrine. I know that is not the best example but I hope you get my point. The film making world tends to forgive "close to Christian doctrine" when it is incorporated in a fantasy film. Also remember that they haven't cut Aslan out of the series and he is about as close to Christian doctrine you can go when it comes to symbolism. I don't believe they will cut out the "Better Narnia" at all.

Oh I don't think they will cut out the "Real Narnia". As worldly as these film makers are it is a fantasy film that they are making here and will treat it as such.

That makes me feel better.

I've always wondered what they will do about Tash as far as special effects go, since he's supposed to be very threatening. And what about the train accident? That could end up being pretty graphic depending on how the director at that time wants to portray it. "Real Narnia" probably won't be cut out because of the important element it adds to the story.

And what about the train accident? That could end up being pretty graphic depending on how the director at that time wants to portray it.

Hmm...........Well, we're not supposed to know there was a train wreck until the end. Eustace and Jill think the jerk sent them into Narnia. I think Eustace says something to the effect of "I thought that jerk was the start of a railway accident. So I was glad to find us here instead."

So, don't show the actual wreck. It could run something like this:
Shot of Digory, Polly, Lucy, Eustace and Jill on the train. Digory is giving Eustace and Jill last minute instructions. The train is moving extremely fast.
Shot of Peter and Edmund on the platform. Peter is holding the box containing the rings. Edmund mentions that their parents should be on the train. Peter doesn't really notice what Edmund said because he's watching the train.
Peter: "Ed, is it just me or is the train coming in too fast?" Edmund looks down the track at the train.
Edmund: "It's--"
We hear a loud screeching noise, there's a blinding flash of light.
Shot of Tirian waking up tied to the tree. Eustace and Jill land on the ground in front of him.

Do you think when jill goes to rescue puzzle and Tirian goes to rescue Jewel that there will be any, uh, killing? Any minor battles there?

I don't know. It's certainly a possibility. I think it would be better to be more of a cloak-and-dagger sort of thing than a skirmish, but that could be just me.

They probably will have something there. I also would much rather have it be a cloak and dagger thing. Sneaking around in the dark like ninjas, peering around corners, tip toeing up behind someone, all in black. ooh, I can see it all now.

Making the actual last battle more EPIC would ruin, imo. In the book, there are only a few Narnians and we've gotten to know most of them. We're emotionally invested in them. Huge armies squaring off against each other tends to be fairly impersonal.

I totally agree. I really hope they don't make it bigger (but that's kind of a false hope). What made it so poignant was the fact that it was so small yet so critical.