Instructions
Download the PKG file you want to install onto the PS3 through the USB port.
Insert the USB pen drive into the computer's USB port. Click the "Open folder to view files" option from the "Autorun" window that comes up.
Right-click the PKG file that you downloaded. Click the "Copy" option from the context menu that comes up.
Right-click the USB pen drive icon that is now on the computer's desktop. Click the "Paste" option from the context menu that comes up.
Unplug the USB pen drive from the computer. Insert the USB pen drive into one of the PS3's USB ports.
Select the "Install Package Files" option from the PS3's menu under the "Game" tab. Select the "PKG" file from the list that populates. The PKG is now installed on the PS3.