I need to put a video in an iPhone 5s frame? How is this done? Something like mockuphone.com. I need to put VIDEOS in an iPhone frame. I have a Mac on OS X.

How can I do this?
You could download one of the product images available at: http://www.apple.com/pr/products/

And then simply overlay the video in iMovie or another video editing software. Those images have special licensing requirements on them so know what you are getting into.