WiFi usage in the UK and US is growing dramatically as sales for WiFi-enabled smartphones, in particular the Apple iPhone jump, according to figures from AdMob, which operates a mobile advertising marketplace.
AdMob collects and analyses handset and operator data from every ad request in its network.
In November, 8% of ad requests in the UK were on WiFi networks, this was up from 4% of requests in August.
After 
the iPhone and similarly WiFi-enabled iPod Touch music player, the Nokia N95 and other N series phones are also driving higher WiFi usage from mobile handsets.
It was a similar picture in the US, said AdMob, where the market is strongly influenced by the Apple iPhone.
Worldwide requests from iPhones grew 52% month over month to 359 million in November, giving the iPhone 6.3% of total ad requests. In the US the iPhone is leading WiFi-enabled handset 
with 9.9% of requests.
In the US, 42% of iPhone requests are made from WiFi, notably higher than most other WiFi capable phones which average between 10-20%.
Another high profile smartphone, the G1 (HTC Dream) generated 15 million requests in November and represents 7% of all T-Mobile traffic. Android had a 2% share of smartphone operating system traffic in the US.
The full November 2008 report with additional data and all previous reports are available for free download.