I often visit YouTube to watch videos and sometimes I download videos from YouTube to put on my iPod. YouTube videos are in FLV formats, so I use a free online FLV converter to do the conversion:
Firstly, go to YouTube and open the page of the video you want to put on your iPod. And you will find the YouTube URL of this video to the right of the playback window. Then copy this URL. See the highlighted area in the figure below:

Secondly, go to http://vixy.net/ , paste the copied URL into the URL field of this web page, and select "MP4 for iPod/PSP" from the "Converts to" drop-down list. Then click "Start" below this list to start the conversion. See the highlighted areas below:

Finally, after the conversion, this website will provide a download link for you to download the converted MP4 file. When you see the link, you can just download the final file from the link, save the downloaded MP4 file on your computer and use iTunes to sync it on to your iPod.
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