Else use: Cheatup.

This program allows you to update your cheat databases for serveral cheat programs on your PSP.
All you have to do is sellect what programs to download DB`s for and be connected to wifi.

Can not get more easy.

Else make them yourself or try to google them as said above and put them in by hand.

 

Once your database has been updated boot a game.
Hold down sellect untill the CWcheat menu comes up.

Under: Select cheats.
All cheats you in your database should be listed for the game running.

Turn on those you want by pressing X then press O.
Now select: Cheats Enabled Yes.

Doing this should enable the codes you selected on the select cheat screen.
If no for your game no cheats list perhaps there is non.

But try CWcheat on another game you are sure that has cheats.
Just to see or CWcheat is functioning properly.

 

If you know how to edit codes, you should know how to add codes. To add/edit codes use CWcheat Database Editor, you can get it from cwcheat.consoleworld.org
I'm not going to tell you step by step how to add/edit codes with cwcheat database editor, it's really easy, just try and you'll understand
For PSX games, cwcheat can take gameshark codes.