Hi Nancy,

What format are the video files? They'll need to be in either mpeg4 or H.264 format for your iPod. If the files are in another format, you'll need a converter.
Have a look at post #14 of this thread for info about adding video to iPod & links to converters, forums etc.
Transferring music to iPod & iTunes

If you're using a Mac, someone recently said that the iSquint converter was good. I'm using Windows XP & use 3GP_Converter. Videora's another free one for Windows that's popular (not sure whether these are compatible with vista, though). You'll find info about Videora & 3GP in the thread above