If you have an iPhone/iPod device that supports video, you can use iTunes to add or sync videos to it just like you do with your music.

1. Connect your device to your computer, then launch iTunes.
2. Select your device from the iTunes Source pane.
3. Select the Movies tab.
4. Check the 'Sync movies' box, then either choose the "All movies" option, or the "Selected movies" option below. For the latter, remember to check the muvees that you want to sync.
5. Click 'Apply' to sync your muvees to your device.