I finally managed to hack my PSP to a custom firmware so I can now run homebrew applications. So far, I have MAME4ALL which is an arcade emulator. For it, I have Pac-Man Plus, Pac n' Pal, and Lode Runner (which is EXTREMELY addicting).
I also have PSPGenesis for the genesis version of Mortal Kombat, since DGen couldn't run it and MAME4ALL couldn't run the arcade version.
Another emulator I got was Daedalus R13. This is an N64 emulator (the only one for it), and it's not that good. It can only run about 5 games at near full speed, and that's only with sound. About 20 other work almost full-speed but without sound, which I can't stand. So the only games I have for it are Bust-A-Move 2: Arcade Edition, Rampage: World Tour, and Rampage 2: Universal Tour. I used to have a lot others, but I deleted them all because they didn't run properly.
Finally, I downloaded 2 ISO's/CSO's. The first was Midway Arcade Treasures: Extended Play to play the arcade versions of the Mortal Kombat games. I also downloaded the demo for God of War: Chains of Olympus, which is the BEST game I've ever played for the PSP, and it's only a demo (lol). I can't wait until the full game comes out, and I'll buy it not download it. That's all for now, but I'll be getting more soon.