PSP Power Saver turns off the UMD driver when you are not using it. This should save you about 5% of your battery power.

Changes:

-Fixed compatability issue with the 5.03 Gen-A firmware, some funky shutoffs were going on
-Cleaned the source up (NOW CLOSED SOURCE, due to a certain someone that I thought I trusted, modifying it and causing a rukus)
-Added vsh support

http://forums.qj.net/psp-development-forum/154206-psp-power-saver-v-0-1-1-a.html