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.
How to upload iPhone video to YouTube
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”.
Log in to your YouTube account.
Enter video information Title, Desc, etc.
Tap Category to choose the right category and then tap publish.