You don't know?
First off get PSP Video 9, it's free, easy, and awesome. http://www.pspvideo9.com/Download/
Second off, to get vids off of youtube just type in the ULR of the video, but put in 'kiss' before youtube.
(www.youtube.com = www.kissyoutube.com)
Then just follow the instructions, and badda-bing badda-boom! There is your vid!
News on TF3!!! Portal 2 Demo!