I just started this myself for the purpose of creating my own customized panels. (Expand Selection by +/- 1 pixel button!)
First, I went and downloaded Configurator from Adobe Labs.
Then, I downloaded the documentation for scripting in Photoshop. It actually walks you through the beginning phases of getting an actual script running.
I'm still a total beginner at it, but I've already made some scripts that work. And, I've gotten halfway there without ANY scripting using Configurator. This opens a whole new realm of PS application!
Best of luck.
