If you want to upload video directly form your iPhone to YouTube, there is an option do that. Follow the given instructions to upload videos to YouTube form iPhone 4 or 3GS.
Note: Make sure your video is no longer than 15 minutes.
Create an account on YouTube if you don’t have one.
On your iPhone tap icon while viewing video and then tap “Send to YouTube”.
Enter video information Title, Desc, etc.
Tap Category to choose the right category and then tap publish.
how do i upload a video that is longer the 15min from my iphone?
To upload video on YouTube longer than 15 minutes, please follow this link https://youtube.com/my_videos_upload and click the increase your limit link.