Great trick to convert video from YouTube to .mp4 without any software
tricks November 12th, 2008
For example you wanna save following video from youtube.com http://www.youtube.com/watch?v=YXRH50fvHWA as mp4 file on your computer. Just add mp4 after http://www.youtube and before .com in the address bar, e.g. http://www.youtubemp4.com/watch?v=YXRH50fvHWA and click on it. On the opened page you will get the link to download mp4 file. Save Link As from context menu of your browser (click right mouse button on the link to display context menu). Now you can add that file to your iTunes library and synchronize with your iPhone/iPod.
Feel free to ask if something is not quite clear.
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also you can use similar service KeepVid.com