This is an editor for GraphViz, an excellent program imho for both quickly
creating a graphical overview of some collection of related components as
well as drawing graphs for systems which are too complex to manage using
conventional drawing programs.

TINTFU can parse DOT files and render a preview of them in a side pane, while
allowing each and every attribute of Graphs, SubGraphs and Nodes to be edited.
The results of such changes are immediately updated in the preview pane.

WWW: http://tintfu.sourceforge.net/