Here's what Jackson told Empire Magazine:
"You are going to get some serious Dwarvish disrespect of the elves at Rivendell," says Jackson.
"You are going to get more of Hobbiton," says producer / co-writer Philippa Boyens. "We always wanted to wend our way through Hobbiton, but in the end Bilbo has to run out of the door."
"You are going to get more Goblin Town, and the Great Goblin singing his song," adds Fran Walsh, Jackson's other half and fellow screenwriter. "It is a great song, but it was just another delay in terms of moving the story along."
"A number one hit from the Goblin King," laughs Jackson. "Barry Humphries is going to rise up the charts."
"We are putting things in the extended cut that are going to play straight into the second film," explains Jackson, "like this character Girion, who is defending [the city of] Dale using black arrows against Smaug. And the black arrows play a part in an ongoing story, for they are the one thing that can pierce the dragon's hide."
"There are also issues with [king of the elves] Thranduil (Lee Pace)," Jackson adds. "We get some of the reason why he and the dwarves had a falling out - to do with these white gems..."
Sounds interesting to me. I for one am interested in seeing more of the Goblins and imagine a Goblin King song will be a (snot-soaked) riot. And as always, I'm happy to see more of quaint Hobbiton, which in my opinion seemed pretty glazed over in the theatrical version of the film. Let us know what what you think in the comments!