PSNabler v3

Leo has released PSNabler v3, a plugin with your PSP that  lets you get on PSN (on certain games) with older PSN enabled firmwares that have been un-allowed to connect to the Play Station Network.

Instructions:
Copy both psnabler.prx and psnabler.txt to the seplugins folder
next add this line to your game.txt in the seplugins folder:
ms0:/seplugins/psnabler.prx
then go into recovery and enable the plugin

Code:

UCJS-10090 Resistance JAP
UCUS-98668 Resistance US
NPUG-80114 Syphon Filter Combat Ops
UCES-01264 Little Big PlanetEU
UCUS-98744 Little Big PlanetUS

Download

Source