According to AdMob (a leading tracking company of mobile advertising), the iPhone is the undisputed leader in ad requests, demands and holds the most force in terms of the mobile ad world.

With 40% of smartphone ad requests belonging to Apple’s behemoth (compared to 33% in Feb. ’09), makes the iPhone vault into the #1 spot for worldwide ad request market share, which is quite an accomplishment given its only been in existence a few years.

The chart pictured here clearly shows the lead it has over various well known markets, including Android and Windows. Symbian OS actually dropped 9% in ad share requests since February of this year. The Palm Pre ranked a distant 4th, with Blackberry/RIM grabbing a solid 3rd spot.

AdMob is the largest mobile advertising marketplace in the world, serving ads for more than 9,000 mobile Web sites and 3,000 applications across the globe, so this info is pretty concrete.