Legal notice: This voids your warranty (like all homebrews and emulators) and it is illegal to download video games “that you don’t own”. And you need the PS1 BIOS file which is SCPH1001.BIN but you can probably find it on the Internet (illegally).
So, what does this do? It’s an emulator for your PSP to play PS1 games. You need certain files to run it. And it’s kinda slow because games run at 10fps. According to the emulator website it says that it is for PSP versions (I am talking firmware versions) 1.0-2.60. The game runs ROMs that are in BIN or ISO format.
It is available for download here:
http://www.dcemu.co.uk/vbulletin/showthread.php?t=36929
[...] I once reported the news on September 24th of this year. The original emulator was a very buggy emulator that ran games at 10fps max. Well the emulator has improved and games run close to their PSX speeds. It also now supports a bunch of games instead of just 3, they have a list that is viewable here. It now has a new name, the PS1P and doesn’t require you to own a PS3 (like Sony’s own emulator for the PSP requires [probably so they can increase the money in their wallets, a typical Sony ploy]). And it’s free. However the legality of the emulator is a bit iffy, but I am not a law/political/lawyer person so don’t take it from me. [...]
after i do this how do i get the games
You have to either get a ROM dump of the game from the internet (illegaly) or make one by coping a PS1 disk on to your Computer (could be illegal) and make sure it is a BIN or ISO format. Then put it on a PSP Memory Stick.