http://www.vconversion.com/
This works online- it will only convert youtube videos, not any flv video -
after conversion you will need to download the conversion onto your hard drive. It converts youtube flv into .mov, dvd, mp4 (iPod)or grab music into .mps or .wav. This program will let you put video on your iPod or rib the audio from it to save battery power. Win WIn either way.
enjoy