Jason Snell at Macworld has written up a quick guide to taking the cool slow-motion videos shot by the iPhone 5s and editing them on the Mac. Since iMovie and other editors can handle different frame rates, they see the slo-mo videos as just being 120 frames per second (fps), which means they play back in real time. But you can take advantage of all those frames and define slow-mo sections.
How to Use iPhone 5s Slo-Mo Videos on the Mac
Jeff Carlson | Never Enough Coffee Creations 