Its Scriptwriting month in deviantART! `Beccalicious contacted me and mentioned this, so I am writing an article for Script writing for animation! Woot!
Granted, I am not the most skilled writer on earth; however, as a film maker, and story teller, I have to write scripts now and then for my characters. I’m far from being a professional writer (I do pantomime films mostly) but I can research and I think that as artists we have an obligation to share our wisdom with other members of our community.
I don’t really have any advice or information to give you besides this:

Make sure your writing is clear to the voice actors (mood, volume, ect.)
Make your characters dialogue interesting, and natural sounding
You are the voice of the character you are writing for! Use different Vocabulary, attitude, etc for each character to help bring out their personality

And here are some resources for you guys looking to get started in writing for animation/Film.

Programs to write in

A typewriter

I use a program called Celtx for my screenplays and writing for my films. It’s a free download and has many awesome features for writing for Film of all kinds and it even lets you collaborate with others. It’s a fantastic program, and costs you nothing to use it.

There is another program I used to use called Cinergy which worked well, cost nothing, but didn’t have the functionality of celtx. It’s also windows only.

Script buddy

Links & Resources

[link] Make Movies – information and techniques on creating animated stories
[link] - Writing for animated film (article)
[link] - writing for animation (article/information)
[link] – Amazon - Basics Animation: Scriptwriting (Basics Animation)
[link] - Animation Scriptwriting: The Writer's Road Map
[link] - Gardner's Guide to Animation Scriptwriting (book)
[link] - the writers store
[link] - A Few Words about Animation Script Format
[link] - ASIFA: Association International du Film d'Animation

As always you can find some of the film community in the film forum or #deviantARTFilm