Here's how you can download the official YouTube app free for your iPad, iPhone or iPod Touch.
Download the Official YouTube App Free From iTunes
1. Go to the YouTube app preview page in iTunes.
2. Click the View in iTunes button.
3. Click the Free button to download the app.
4. Sync your iPhone or iPad with iTunes to install the YouTube app.
Download the Official YouTube App Free From the iOS App Store
1. Open the App Store on your iPhone or iPad.
2. Search for "YouTube" (without the quotes).
3. Tap the Free button to download the app and install it on your iOS device.
Here's a description and screenshot of YouTube for iOS devices:
"Watch the world’s videos and keep up with your favorite YouTube channels with the official YouTube app for iOS. Sign in to access your subscriptions, playlists, uploads and more.
✓ Enjoy YouTube’s vast video catalog, including official music videos
✓ Find videos and channels more easily with voice search and query autocomplete
✓ Subscribe to channels and instantly access your subscriptions with the channel guide UI
✓ Read comments, browse related videos, enable subtitles and more - all while watching
✓ Easy video sharing to Google+, E-mail, Facebook and Twitter"