Percival and PSP 3D have released Super Mario War v1.0 for the PSP, a port of the Open Source Super Mario deathmatch game, originally developed by Michael Schaffer and Florian Hufsky. The goal is to stomp as many other Marios as possible to win the game.
The PSP version features tons of different characters and maps to choose from, as well as a complete library of music, CPU AI, and a variety of game modes. It's fully modable too.
Those who are using 1.5 firmware will have to wait a bit longer as Percival is still trying to figure out why the game only shows a start up screen then goes black. We'll post the port for the 1.5 version as soon as problems are fixed. The lucky 1.0 and 2.0+ users should have no problems when running the game.