AppTheater.com is ( i belive ) the YouTube of iPhone apps. The site is fairly new , so don’t expect to find as many videos as you can find on YouTube but i believe it will grow very very fast. You can find the exact same options that YouTube offsers you , like embed and comment but there are other options as well like set video details where you can change brightness, contrast, saturation and smoothnes of the video you are watching.
Another thing i really like about AppTheater, is that on every video there is displayed the price of the app and there is an “Buy This App From The AppStore” button as well. All in all there is a great site and i hope it will grow to half the size of YouTube ( that is HUGEEEEEEEE ).
Check it out, upload your own videos, send me a mail , let me check them out.