Want to store a YouTube video on your iPhone? You can't, unless you have MxTube on a jailbroken iPhone. The next time you have a long flight ahead of you and you want to be able to watch a TV show or movie on your jailbroken iPhone, use the app to download and play back YouTube videos at various quality settings.
You can watch clips offline, as well as save them to your computer or hard drive. Take note, though: If you update your iPhone, all your downloaded content will be erased.