In looking for something to help with story planning I happened to stumble across this tool. Haven't actually downloaded it to try it, but thought I would share the article anyway.
Oh wow. I hadn't continued digging past their writeup and story site.
Thanks. I was going to use DIA (open source) to work out the flow on my next big one (after I finish my MHD) entry, but know there is a free browser-based one is cool as well.