Brightpad lets you (fully) control the brightness of your PSP’s screen.

Changes:

Brightpad automatically detects if you’re in-game or in the XMB, if you are in-game, then you’ll HAVE to press two buttons to change the brightness. You can change them both in the configuration file.
While the first button is pressed, Brightpad will not allow the other button presses to go through to the running game/homebrew.
I also did my best to avoid flickering while in-game

http://forums.qj.net/psp-development-forum/167818-brightpad-v4.html