PSP-Hacks.com

from included the readme.txt:

This is a binary loader for the Grand Theft Auto: Liberty City Stories savegame exploit, demonstrating a simple application being loaded on firmware versions 2.01 and 2.50.

It should be compatible with both EU and US copies of the game, and any firmware version that can run GTA.

Installation
============

Make sure that you don't have any important saves in the first slot of your GTA savegames. If you do, then just start GTA, load the first slot, then save in a new slot.

Then just copy the files from the archive to the following places on your memory stick (the example assumes that your memory stick drive is "F:"):

HW.BIN => F:HW.BIN

For US copies of the game:

ULUS10041S0DATA.BIN => F:pspsavedataULUS10041S0DATA.BIN
ULUS10041S0PARAM.SFO => F:pspsavedataULUS10041S0PARAM.SFO
ULUS10041S0PIC1.PNG => F:pspsavedataULUS10041S0PIC1.PNG
ULUS10041S0icon0.png => F:pspsavedataULUS10041S0icon0.png

For EU copies of the game:

ULES00151S0DATA.BIN => F:pspsavedataULES00151S0DATA.BIN
ULES00151S0PARAM.SFO => F:pspsavedataULES00151S0PARAM.SFO
ULES00151S0PIC1.PNG => F:pspsavedataULES00151S0PIC1.PNG
ULES00151S0icon0.png => F:pspsavedataULES00151S0icon0.png