first, imprt the vids to your itunes. next, connect your ipod to your computer. finally, either manually manage your media, meaning that you can pick and choose which stuff you want on your ipod, or just sync your library to your ipod.
Normally its just a matter of taking the video and dropping it into the Itunes list of what is inside your ipod. Just make sure that the vid is in a format that your ipod can read. If you need a video converter try this one, its awesome and does all types of stuff. It can even download and convert youtube vids for your ipod.