I missed Soundbeam when it came out a few months ago. It’s a visual spectrum and waveform analyzer for iOS. I’m not sure about the license attached to recording it’s video output but I think this would be cool to use in a promo music video (update: in a Tweet the developer said it’s ok to use Soundbeam’s visuals in your own videos as long as you send them a link to what you created).
“Soundbeam is an audio analyzer that processes the input of your microphone in real time displaying it like a classic oscilloscope.” – evilwindowdog.com
For more info: evilwindowdog.com