Things You'll Need
Instructions
Insert the Memory Stick Pro Duo into the PSP by sliding it into the slot on the right side of the console. Make sure you are using at least a 1 GB card, so that you can fit the typically large MP4 video file on your Memory Stick.
Plug the PSP into your computer using the PSP USB cable. Plug the smaller end of the cable into the port on the top of the PSP console, and plug the other, larger end of the cable into a USB port on your computer.
Go to the "Settings" menu on your PSP and select "USB Connection." The PSP will appear as a removable device on your computer. Open "My Computer" to view the device.
Choose the location on your computer where you have the MP4 files. Drag them to the PSP.
Disconnect the PSP from your computer by right-clicking on the device in My Computer and selecting "Eject" from the menu that appears. Unplug the USB cables.
Go to the video menu on the PSP and press "X" on the video you wish to watch on your PSP.