I recently learned that you can download Youtube videos using Zamzar. It's really pretty simple. They will send you an email once the file has been converted and you can download it and save the file to your computer. I'm excited to use this since our school has breakfast in the classroom and this is an excellent time to fit in these educational short videos.
I just discovered that apparently you can also download the files with RealPlayer too! It's really awesome and has many different options. You can download to an iPod, iPad, or save it to the computer and view in RealPlayer.