Assuming you have dot installed:

http://en.wikipedia.org/wiki/DOT_language

Also, these are useful:

http://www.graphviz.org/pdf/dotguide.pdf

http://linuxdevcenter.com/pub/a/linux/2004/05/06/graphviz_do...

Thanks

Another good example is in the book Land of Lisp. Chapter 7 and 8 makes a game, Hunt the Wumpus, using Graphviz:

http://landoflisp.com/source.html (check out graph-util.lisp and wumpus.lisp)

Chapter 8 is even available as a free download:

http://nostarch.com/download/Lisp08.pdf