Apptamin's blog gives iOS app marketing advice, covering analytics platforms, beta users, App Store optimization, and app critiques.
HN commenters link it for app marketing guidance and note that App Store success depends on search ranking; one couldn't view its .ogv videos.
Being successful on the app store involves a bit more than making a great app. It's how you play the search ranking/rating game. There are quite a few things that need to be done right.
The way you get ranked in Search plays a huge part in your sales (Unless it's a top 50 app). Another huge factor is your screenshot. Your leading screenshot should not be a shot of the launch image. Here's more info on screenshots: http://mobile.tutsplus.com/tutorials/mobile-design-tutorials/app-store_screenshot-design_iphone-desig/
[1]: (App Store Optimization Cheat Sheet [PDF]): http://www.apptamin.com/ASO_Cheat_Sheet-v2.2.pdf
I wish they were GIFs. Actually the are .ogv which I can't see on my Android tablet (and probably neither on iOS). I had to go to the computer to see them.
To answer you're question: I have no direct experience but check this http://www.apptamin.com/blog/capture-iphone-ipad-screen-video/