Mac OS X: Photo Booth and iChat's handful of native effects are fun, but the novelty of making yourself glow sepia wears off pretty quickly. Fortunately, you can easily tweak some settings to add a bunch more.
Macworld's Rob Griffiths unearthed a way to add more than 20 silly effects to the 16 that are already found in Photo Booth and iChat. By cutting, pasting, and lightly editing a collection of files already hiding inside your Mac, you can pixellate, posterise or ASCII-ify yourself all you want.
Check out Griffiths' post for a step-by-step tutorial on exactly how to modify your files. Don't worry, you won't be digging into the bowels of your system in any serious way, so any mistakes you make are easily correctable on the off-chance that something goes wrong.
Add More Effects to Photo Booth and iChat [Macworld]