I dont have an iPhone but a few of my buddies
I have just hit up my buddy he says the trailers work on his iPhone, and play within Safar its self.
looking at the page in FF via the user agent switcher I see some JS but not sure if its required and also the embded div container
HTML:
<div id="movie-container">
<embed src="http://movies.apple.com/trailers/iphone/images/greenband_320x133.png"
href="http://movies.apple.com/movies/disney/wall-e/wall-e-tsr1_p320.m4v"
target="myself"
width="320" height="133"
controller="false"
autoplay="false"
scale="1" cache="true"
type="video/quicktime"
pluginspage="http://www.apple.com/quicktime/download/">
</div>
the video file data its self is:
320x132
ACC 44.100 kHz
H264 320x132
FPS 23.98
8.41 megs
So when he views the page and clicks on the play button it launches the iPhone video player (the one used to play videos,music etc when u hit iPod on your iPhone)
Here is a quick screen grab of the iPhone trailer page
iPhone Web Trailer Page