Have you thought about making a custom PSP theme? But, maybe you don't know where to start. Or perhaps you're scared by all the work that goes into it. Sony's official PSP theme guide won't make it any less work to create a theme, but it will give you all the tools necessary to make your own PSP themes. The images necessary require precise specifications, so make sure you follow all the instructions.
The theme program offered is available here (Windows only).