Download YouTube Videos on to your Ipod

Having a local copy of the video means you won’t lose access if YouTube removes the video from their site. And if you convert the video to MP4 format, you can transfer it to your iPod as well.

Doing this appears to be in compliance with YouTube’s Terms of Use, as long as you do not distribute the videos to others, and you retain any copyright notices on the files (see sections 2A and 4).