What is a PSP theme?

A psp theme is really just a change in the icons on your psp. If you open your psp, you will see that on top of game it shows a controller. If you feel like changing the theme of your psp, then go to the PlayStation network store (Internet connection required), log in if not logged in already, go down to were it says "themes & wallpapers", click on it, then click themes, and choose the theme you want for your psp. I hope this helped and enjoy. Note: Some themes cost money to own while others are free of charge.