Dunno about that app. But there are a bunch of free downloaders that will download videos from YouTube and store'em on your idevice. I use Downloader Elite by iMoreApps since it can save the videos to your photo roll. Was free when I got but looks like its 1,99 now.
Foxtube is seriously the best app ever.
It stopped working recently which broke my heart, but they fixed it yesterday and I'm not going to take it for granted ever again.
I love you foxtube! Dont ever leave me again!
Ps yes it caches any songs/vids from YouTube so you can watch them offline as save them to your phone forever and even make music playlists.
I save techno music to work out to, because I can't bring myself to actually buy techno when I don't usually listen to it leisurely.
Currently addicted to: Duet game, Threes, Tengami, Oquonie, Platforms Unlimited, Perloo, Wave Wave