Check out http://www.airsquirrels.com/ they have an app that let's you mirror your iPhone to your desktop. It's very smooth. I use that, and then use a standard screen cap tool to capture the screen on OSX. Result is the ability to do full app demo on your iPhone and have everything mirrored to your screen. Also handy for sharing via a projector... Since it all goes over AirPlay you can demo without needing a cable/dongle off the iPhone.