That is there because thats the symbol that appears when you need a plug in to view a certain page that you don't have. Like flash for example. Theres no way to get rid of it because you cant get flash on iPhone.
I must say I love the piece of Lego. My particular favourite right now is the Rogers iPhone page where they prompt you to take advantage of their music and ringtone/trax downloads however the pages almost all require plug-ins that aren't supported. Solid forsight on that one!