Place theme.p3t file in X:/PSP/THEME/ folder and select theme from XMB->Settings->Themes
X is your psp USB or PSP media card
Or Download Only theme file directly from your PSP internet browser.
Description:
This is my first theme. I made the images on paint so I didn't know how to take the white background off. My next one will be better.
*SPOILERS*
Mario Galaxy
