[PSP] Cheating on PSP

Hiya,
I was looking all over the net for a cheating "thing" on the PSP...
Something like an Action Replay for the PS2.
Now, I know that there IS already an Action Replay for the PSP, but it doesn't quite do the same thing. Instead of having cheatcodes for games, it lets you download and upload savefiles.
So does anybody know of a "thing" for the psp that could have cheats for games?

Thanks!

P.S. I'm using firmware 3.51 M33 (flashed)

Offline or online?

offline

use CWcheat its a plugin for the psp but you need custom firmware

CWcheat can also be used online.
Damn hackers @ killzone =(

can it be used with 3.51 M33? cuz i think that's pretty custom =D