It was too late to record a video with my iPhone. So I settled for a ScreenCast with ScreenFlow.
I quickly made a background in Keynote and then to a 1080×720 screenshot of it with Skitch.
The voice over was recorded on my Roland R-05 digital recorder and then processed in Adobe Audition. I was surprised how much of what I recorded was never used in the final production.
I used Skitch again to take a few screenshots.
Then I edited it all together and presto.