Instructions
Turn the PS3 on. Connect the USB flash drive to any USB port on the PS3.
Move to the category on the XMB menu (the selection menu that first loads when you turn the PS3 on) that best represents the type of file you want to transfer (e.g., a movie clip would be under the "Video" category).
Select "Display All" to bring up a list of all of the files in that category. Select the file that you want to move to the PS3. Press the "Triangle" button on the controller and select "Copy." The file will be copied from the USB flash drive to the PS3.