It's been revealed buy a gossip writer who says she had a leaked breaking dawn script, that we'll see Bella and Edward die in breaking dawn.
Don't worry they haven't changed the story that much.
What happens is Alice shows Aro what will happen if he continues with the battle.
In which Edward and Bella kill Aro, but then in turn get killed themselves along with others.
So we'll get to see the battle we were all waiting to read but never happend.
Here's the main source of the story:
http://www.laineygossip.com/Vampire_sex_in_Breaking_Dawn_Part_2_and_spoilers_08dec10.aspx
xxx