Instructions
Turn your PSP on and select the "Browser" icon. Go to "www.m.youtube.com" and wait as your PSP connects to the mobile YouTube site.
Select a video or search for a specific video using the "Search" bar at the top of the YouTube website. This will save the YouTube video URL in your history.
Press the "Triangle" button to bring up your browser menu. Go to "www.Keepvid.com" or "www.catchyoutube.com." Select the "Download" field from the page that appears.
Press the "Select" button three times to bring the YouTube video URL up. Then click the top-right corner button, "History." Press the "Start" button.
Select "Download MP4 High Quality" and a window will appear. Select the "File Name" field and name the video file. Press the "X" button to save the video file. Exit the browser when the download finishes and select the video in your PSP video section.