If you also have Kazaa, you'll find all of them on there including the exclusive commentary ones.
From CartoonNetwork.com they are only available to U.S residents, and StarWars.com offer them to Hyperspace members.
If you have Quicktime Pro, once you have downloaded them to watch just save them as self-contained movies to your hard disk. Or look in your Temp. Internet folder as you can find them in there if enough space is available.