This question came directly from 2 friends of mine of facebook - Andy & Heidi. They asked me whether they should use a script whilst presenting on camera, especially if they are outside presenting, doing their online video marketing videos.
In this video I go into a fair bit of detail about how I communicate on camera and when you should do this:
Learning the script
Using a teleprompter
Using PowerPoint Slides
Using Memberable Structure
Just so you know, never learn the script!
If you're just getting started and want to find out more information about how to get started with video, I strongly recommend you watch this video too: http://www.youtube.com/watch?v=ZXvHKL1OD78