According to AdMob, which serves ads for more than 6,000 mobile web sites and 400 applications around the world, worldwide iPhone requests grew 86% month over month to 668 million in December, giving the iPhone a 10.8% share of total requests. Further, according to the report, the iPhone OS has already surpassed the RIM OS and Windows Mobile combined. iPod Touch has been enjoying huge growth as well. As you can see in the pie-chart, in the US, in December, iPhone generated a whopping 48% of smartphone requests, up from just 9% in May.
The report released by AdMob is very interesting and can be viewed in full detail here.