I have used Visio for this too but have been watching this thread in
case there is something better. Visio is dumb easy and you can download
libraries of graphics for your industry... When i have needed to create
flow charts for use in marketing materials I have to fallback to
Photoshop for higher quality however.... but that doesn't sound like
your deal.
if you take a look at "mind mapping" software, you get the added
benefit of managing connections and viewing relationships rather than
just visually mapping static stuff. i like personalbrain
Alpay Kasal
Artist/Engineer
blog:
http://blog.LitStudios.com
twitter: @alpaykasal