If you are using the bittorrent client Vuze it has a new feature called Devices. Enable this, drag the movie on to it and it will ask you which sort of iPod you have. It will then convert the movie into the right format and shove it into iTunes. If you are not using Vuze then you need to convert the movie to a file type iTunes understand (don't know off hand) but there are many apps that can do this. Or open up the movie in Quicktime, if you can, and from the Quicktime menu choose 'Export' and export it, say, on to the desktop, having chosen the format for iTunes. Then drag it into iTunes.