How can I download YouTube videos to my iPhone?
The YouTube iOS app is great when you have a data connection. What about when your iPhone or iPad is offline? There are several App Store apps that make it possible to download YouTube videos directly to your device for offline viewing anytime. Many third-party apps also have the benefit of other features not found on the official YouTube iOS application.
Here are some iOS apps that will download YouTube videos to iOS:
($2.99) VIATube [4.5 stars, 10 ratings]