Yep
Celtx is it. I played around with it for a day or so. It is really more for someone writing their own script, comic, or
screen play... and then producing it.
First you have to have a text copy of the script, which of course has all kinds of potential legal issues. Once you have the script you can go through it, highlight a word and then assign that word to a
category. So for example if the script says, "Look out it's a
snake!", you can highlight the word
snake and assign it to the
props list. Or you can take the
stage description of what an actor's costume looks like and put it on a costume list. It's useful... but I'm not sure how much more useful than just sitting down with a spreadsheet.
The biggest disappointment is the Notes feature. You can pick any
point in the script and add a note. This at first sounds like a great way to add in cues or
blocking. But it just isn't executed in a way that would really help an SM. It's close and could probably be REALLY useful with a few tweaks. But it's also free so who's complaining.
They have a bunch of little symbol packs they sell which again look like an interesting solution for
blocking. They are inexpensive and how they make their money. I didn't buy one, but I don't think they are the right symbols.
So, it's close, but not quite what we are looking for. Hey Celtx, if you're listening we would be glad to tell you how to tweak it to be the ultimate theater tool.