Instructions
Download the Sei PSP Tool onto your computer (see Resources).
Plug the USB cable into the "USB" port on the side of your Sony PSP, then plug the other end of the cable into an available USB port on your computer.
Press the "Menu" button on your PSP, then scroll to the "USB Connection" option and select it by press the "X" button.
Double-click the Sei PSP Tool icon on your computer to launch the application. The application will automatically detect the PSP connected to the computer.
Enter the desired name for your emulator on the PSP in the Name entry box in the main window of the application, then click the "..." option.
Scroll to the "EBOOT.PBP" option in the Emulator setting on the application window, then select "PSP Unit" from the drop-down menu.
Click the "Generate" button to automatically install the necessary file system to your PSP device.