Can you play PS ROM's on a PS2 emulator?

There have been some Nintendo DS Emulators developed by some kind souls, however these products are called Homebrews and they require the use of a PSP with Custom Firmware. It can be a difficult process however you can research the information on google and see how you can go about downgrading and moding your PSP so it can play Homebrews. However this is potentially damaging to your PSP and can lead to bricking (aka making it basically useless).