What format should videos be for an ipod?

I Got a Black Video Ipod for my Birthday.
I got Music and Photos on it.
but Im having a Bit of Trouble wiht the Videos.
I have videos on Itunes,
But whenever my ipod syncs,it says That they couldnt be uploaded
Because My Ipod cant play them.
What Formats...

do Videos have to be in for An iPod?
And where can I download ipod stuff for free?

Ipod videos use an MP4 format. This is mostly exclusive to Quicktime and Apple products like the Ipod. Itunes videos are usually downloaded in MP4 format for copyright reasons, so transferring them to your video ipod shouldn't be an issue. It is more than likely an issue with syncing the videos properly.

Make sure that you are syncing the videos properly. Try making a playlist.

Actually, iPod support MP4, M4V, AAC and MP3 formats. iTunes can help you to convert MOV files to MP4 format. Also you can use the 3rd party software to convert more kinds of format of multimedia files besides MOV to the formats that iPod support. I always use Aimersoft Video Converter where you can find it on http://www.aimersoft.com/video-converter.html