Actually... I already did that. The problem is, even if you find a good PSP emulator (and there aren't many of them esp. for Mac), you still need to decompress the CSO file into the ISO game. When I did this, I got a folder full of every single image, sound and tidbit of code in the game, which would actually be kind of cool if they were in a format that I could open.
I prefer real games though. When I'm on the computer, I come to the Internet and do stuff or top open Microsoft Word and work on my school projects. Not play games.
So even if I have emulators downloaded, I rarely use them. I have znes on my comp currently, btw. I use it to play Gradius 3, Kirby's Dream Land 3, and Kaizou Mario(the bastard hard hacked and reconstructed version of Super Mario World)
The only games I'm emulating right now are Earthbound and Yggdra Union. In the past I've emulated the MMBN series but when I tried again they made my computer crash and deleted my Yggdra save file, so I stopped trying.