As requested, here are some good links to various sites on the interrelated topics of chaos theory, complex systems, nonlinear dynamics and fractal geometry. I found these sites to provide a solid introduction to the subjects while keeping the mathematical aspects straightforward and manageable. Hope you find these interesting and useful.

http://amath.colorado.edu/faculty/jdm - Professor James D. Meiss Homepage
http://www-chaos.umd.edu - Chaos at Maryland
http://www.duke.edu/~mjd/chaos/chaosp.html, An Introduction to Chaos Theory and Fractal Geometry
http://hypertextbook.com/chaos/ - The Chaos Hypertextbook
http://www.imho.com/grae/chaos/chaos.html - Chaos Theory: A Brief Introduction
http://www.imho.com/grae/chaos/fraction.html - Math and Real Life: A Brief Introduction to Fractal Dimensions
http://math.bu.edu/DYSYS/ - The Dynamical Systems and Technology Project at Boston University
http://www.mathjmendl.org/chaos/ - Chaos Theory and Fractals
http://order.ph.utexas.edu/index.html - The Ilya Prigogine Center for Studies in Statistical Mechanics and Complex Systems