After some initial hacking on my PSP, I have been working on my first port for the PSP.
I choose the SDL/GL game "Chromium B.S.U.", which is a nice space shooter arcade game.
I think it has not been ported yet, sorry if I missed another post.
The archive for firmware 1.5 and the source code are available on my website: http://royale.zerezo.com/psp/