Click on the desktop edition link near the bottom of the page, and it should take you out of the mobile version of the webpage, to the desktop edition. Is that what you're talking about?
nope, all 3 are mobile versions.. the Droid Inc, and iPhone load up a cool highly configured version of the desktop client, but for mobile browsers.. shows a cool mobile fitted background under your search bar. All 3 are going to the exact same URL.
I'm pretty sure I heard that Microsoft was paying megabucks for agreements with carriers to feature Bing in some of their cell phones, in particular the Verizon Galaxy S version.