Things You'll Need
Instructions
How to Install PSP Games
Update your PSP firmware to version 3.52 M33 or higher. This is a homebrew firmware update that will allow the PSP to run games directly from a memory stick. (See Resources).
Insert a memory stick into your PSP, then place a UMD into the proper slot of the console. Power the system on and you'll be taken to the main menu. Press "Select" on the PSP to access the M33 VSH menu. Navigate to menu item labeled "USB Device" and change the setting to read "UMD Disc."
Plug one end of the USB cable into your PSP and the other into the USB slot of a computer. The computer can be on while making this connection. On your PSP's main menu, scroll down to where it says "USB Connection" and select it by pushing "X".
Select the ISO file that has appeared. This file contains the game that you are going to install onto your PSP. The file will be several digits, and not the actual name of the game. Drag the file to your computer's desktop and rename it for easier navigation.
Keep your PSP connected to the computer and exit USB Mode on your PSP. Once again enter the M33 VSH menu on your PSP (push "Select"). Under the "USB Device" setting change it from "UMD Disc" to "Memory Stick". Save your changes, leave the menu and go back into "USB Mode".
Click on the ISO file located on your desktop and drag it into the folder that opened on the computer when you put your PSP into "USB Mode". You are placing the game onto your memory stick, making it accessible directly from the device.
Disconnect from your computer and leave the "USB Mode" of the PSP. Access your newly installed game by selecting it from the "Game" menu under "Memory Stick".