Instructions
Download the iPSP installation package.
Double-click the iPSP package icon to unzip the folder.
Plug the USB connection cable into the "USB" port on your PSP, then plug the other end of the cable into the USB port on your computer. A folder for your PSP will appear on your desktop automatically.
Drag-and-drop all the files from the iPSP package into the PSP folder's "PSP Tunes folder, inside the "ROOT" folder of the memory stick directory. You will see a prompt asking if you want to "overwrite" the files. Click the "Yes" button.