PSP298 has released a new Gameboy Advance emulator for the PSP, this release has great speed although not 100%, it uses the full 333mhz speed, it s full screen and it also uses what looks like is the Rin file selector and can be fully configured.

Heres some screens:

Download here -->

This is a much better GBA emu for the PSP than the other one and the speed will impress.