Another great resource about fractals and l-systems is Jeffery Ventrella's "Brainfilling Curves", which is also available for free online to read and download: http://www.fractalcurves.com/
And Darwin Pond too! Most engaging artificial evolution simulation I've ever seen. http://www.ventrella.com/Darwin/darwin.html
Edit: I've been looking for this forever. Thanks for the link.