According to the latest report from AdMob, the iPhone has usurped 50% of the smartphone Web traffic in the U.S. RIM comes in second place.AdMob issued a new report on its findings of mobile ad traffic over the last few months. Some interesting statistics have popped up.

Looking at actual phone models, the rankings are as follow:

• iPhone - 49.5%
• BlackBerry 8300 (Curve) - 9.1%
• BlackBerry 8100 (Pearl) - 6.9%
• Palm Centro - 6.0%
• HTC G1 - 5.2%
• Danger Sidekick II - 3.4%
• BlackBerry 9530 (Storm) - 1.7%
• Samsung BlackJack II - 1.6%
• HTC Touch - 1.0%
• Motorola Q9c - 0.8%

The real success story here is the HTC G1. It has managed to capture over 5% of the market in just three months' time. It managed to grow its market share as RIM, Windows Mobile and Palm OS all declined in the rankings on a platform level.

What's also interesting is that the Curve and Pearl -- two older BlackBerry models -- completely outpace the new Storm in generating Web traffic. In my experience, the Storm has a far better browser than either the Pearl or the Curve. The number of Curves and Pearls in the market -- both of which have been for sale for years -- is clearly playing a role here.

In any event, Apple has the U.S. mobile browsing market pretty much conquered right now. Can Palm's Pre make a dent when it goes on sale later this year?