Since iPod only support MP4, M4V formats, I think you may need software to convert videos. I prefer to use Aimersoft iPod Converter Suite for conversion. I think a link to a step-by-step guide page will be helpful:
Convert to mp4 format drag to movies under devices. else drag to movies under library,select it goto advanced-select conversion for ipod after conversion drag to movies under devices. note:mp4 format is a must.
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