We teach kids many forms of writing. Scriptwriting is a very relevant form these days. Pens to Lens is a site specifically designed to help teach this form of writing. There is a lot on the site including a useful teachers’ guide with several good resources.
I particularly like two resources. Worksheet B is a style guide which outlines the proper format for a screenplay. The Sample Script is really good as it is a short excerpt from the Toy Story script. It’s from the scene when Buzz and Woody meet the Aliens in the Crane Game. Think “the claw, the cla-a-a-a-w!” It would be good to use with kids as they’ll know the scene and then be able to see how the script is written for it.
Where Pens to Lens is full of good resources for teaching script writing, Celtx is a free online app for actually writing a script. Of course a script can be written in any word processor or text editor but Celtx helps with the drudgery of formatting a script. It helps free the writer from formatting so he/she can focus on the important part–telling his/her story.
Using Celts involves signing up for an account. The account is free. Scriptwriting is always free. There are other features in Celtx but one has to pay a subscription fee for them. For our needs, the free version should be enough.