How to delete YouTube video on your iPhone?

How to delete YouTube video on your iPhone?

Do you mean the app?
Pre-iOS 6: You can't.
iOS 6: Delete the app.

Do you mean YouTube videos you've saved on your iPhone?
Go to iTunes and uncheck any videos in your video library. When you plug in your iPhone, it should delete them. Alternately, uncheck the "Sync Videos" option on the Sync page for your iPhone.

I don't think you can.