Here’s a really cool iPhone DIY that shows you how to jazz up iPhone 3Gs videos with iMovie. I am sure there will be an app for doing this later down the road but until then, you can use this method to quickly make your videos optimized for the iPhone 3Gs.
it’s so easy to do that I decided to whip up a quick tutorial showing how this works. You probably have a tool on your Mac that can do the job for you with just a few clicks, drags, and menu selections. iMovie is the perfect easy tool for creating full feature films (just kidding) from individual scenes shot with the iPhone 3GS video camera.