If the video format is MP4 or H264, you can sync it on your ipod directly. If not, you need a converter, because ipod only support the above format. If you want watch videos on your ipod, I recommend you a nice tool called 4Videosoft iPod Video Converter. It can help you convert all video like MPG, MPEG, MPEG2, VOB, MP4, M4V, RM, RMVB, WMV, ASF to MP4, MP4 AVC format for your iPod/iPhone
You can free download it on the following website.
http://www.4videosoft.com/ipod-video-c…
Hope my advice can help you.
You should make sure the video is MP4 or H2.64 format, the audio is Mp3 format for iPod. You can try this iPod Video Converter Suite to rip DVD movie and convert videos in any format to iPod. It is the fastest converter I have used.
Refer this step by step guide:
http://www.dvd-video-converters.com/dvdv…
You can try Cucusoft iPod Video Converter Suite to rip DVD movie and convert videos in any format to iPod. It is the fastest converter I have used. You can download this software free from here:
http://dvd-video-converters.com/dvdvideo…

DVD ripper is a computer program that facilitates copying the content of a DVD to a hard disk drive.

DVD Ripper can rip DVD to AVI MPEG WMV DivX H.264/MPEG-4 AVC MP4 MP3 WMA excellently.

pavtube is one of the best dvd rippers, It is versatile application and users can use it either to backup DVD to hard disk or to convert DVD movies to AVI, WMV, MPG, MP4, MOV, and 3GP, AAC, MP3, W4A, WMA, WAV and AC3 etc.

Unbiased reviews and side-by-side comparisons of ipod converter suite you are considering, and gives you enough information to research the ins and outs of a particular product, you can choose your favorite one here:
http://www.topsreviews.com/reviews/ipod-…
For mac users:
http://www.macdvdconverter.com/mac-dvd-i…
Some useful information you can get on the official site:
http://www.apple.com