According to the New York Times (reg reqd), screenwriters are using software more and more these days, not only to help them format their scripts but also to help them create:

[Roger S.H. Schulman, who shared an Oscar nomination a year ago for Shrek] suggests that there are times when resorting to software like IdeaFisher, "this helpful little guy who has a million ideas and suggestions," can be a bit like having another writer in the room.

Schulman uses a range of software, including Inspiration, Power Structure, ScriptWright (an MS Word template), and IdeaFisher. The story also mentions Dramatica, Final Draft, and Movie Magic Screenwriter.

If you’re curious about such things, Chuck Frey’s Innovation Tools website has an entire section devoted to reviews and news about creativity and innovation software.

We don't currently use any idea-generation software here, but I can see the benefits. One of the reasons I've posted so little the last week wasn't because of the ice storm, but because we are in the middle of a project and I've been working/playing in the gigantic mass of ideas, idea fragments and idea possibilities - the "stuff" that is the outcome of our consumer ideation projects. West Wing writer Kevin Falls said in the NYT article, "the most important software for writers is still what's between the ears," and that's what I use to get creative, usable ideas from that pile of words.

Software might help organize the words some - and we're looking into that now - but it's hard for me to imagine there's software that could help much! We use software and the Internet to communicate with our creative panel, but often I seem to do better processing the ideas with a stack of print-outs and an array of colored highlighters!