When I viewed the source of your page this morning I saw 2 of them, but now I only see one of them and it is not the correct one.
I'm using the UserAgent plugin for Firefox to set my user agent to iphone 3
what I see in your page at the moment is this:
<meta name="viewport" content="width=670, initial-scale=0.45, minimum-scale=0.45" />
Actually looking into it what you need to do is set PreZoomForIPhone="false" on the <portal:MetaContent control in layout.master as this is what is adding the bad one.
Hope that helps,
Joe