I just ran across this interesting site, AgileDraw.org, that helps agile modelers and programmers produce diagrams. Here’s how they describe it:
Agile Draw is a set of principles and styles for producing diagrams that communicate effectively. These principles can be used with any drawing technique or tools, from whiteboard to pencil and paper to computerized tools. The essence of Agile Draw is to use simple conventional drawing elements such as circles, boxes, connecting lines and text, in conventional ways that give diagrams a sense of life and a consistent way of communicating.
The Agile Draw principles are not new! Agile Draw is a simple summary of things we all know about drawing useful pictures.