Most videos that you can watch on a website (for example, YouTube) are in flv format, which is supported by Zamzar. That should have you covered. If you have access to other video download sites that provide videos in other formats, check the list. Note that if the videos are already in mp4 format, you can just download them directly to your iPod.
Some formats can be converted to a special "iPod" format on Zamzar, but according to the list, some types (such as flv) cannot be converted to it. In those cases, convert the file to mp4. All iPods that support videos will play that format. [ The_MoUsY_spell_checker's advice column | Ask The_MoUsY_spell_checker A Question ]
Attention: NOTHING on this site may be reproduced in any fashion whatsoever without explicit consent (in writing) of the owner of said material, unless otherwise stated on the page where the content originated. Search engines are free to index and cache our content. Users who post their account names or personal information in their questions have no expectation of privacy beyond that point for anything they disclose. Questions are otherwise considered anonymous to the general public.