In reply to adstapleton:
This book is a blast from the past, when fractals were becoming feasible to produce on home PCs and contains some excellent images although might be hard to come by. It looks like it may be on reprint though.
http://books.google.co.uk/books/about/The_Beauty_of_Fractals.html?id=mnhcMQ...
Contains a fair bit of theory too for the interested. I used to run a fractal webpage and created numerous Mandelbrot & procedurally generated 3D landscape programs in C and assembly.
A good program to play around with for making images is XaoS, which was around in the 90s. It should absolutely fly on a modern PC! Looks like something David Bowie might have used
http://wmi.math.u-szeged.hu/xaos/doku.php