Well, i recommand this converter
4Easysoft Total Video Converter
http://www.4easysoft.com/total-video-converter.html
It can convert almost any the video format to another with high output quality.
This full-featured video converter software also can help you:
1.convert between all mainstream video and audio formats,such as(mp4, mov, m4v, vob, XviD, avi, flv, 3gp, 3g2, mpg,wmv,HD videos,etc;m4v, mp3, wav, ac3,etc)
2.extract audio tracks from video files to other audio formats
3.support all popular portable multimedia players
4.edit video-Effect,Merge, Trim, Crop and Snapshot
Here is the detailed guide:
http://www.4easysoft.com/how-to-put-video-on-ipod.html
Hope this can help you.