Given the spotty nature of AT&T’s 3G Network I have often found myself switching on my Apple (s AAPL) iPhone’s WiFi connection, signing up to one of the hot-spots (using Devicescape’s Easy Wi-Fi iPhone Client) to send emails, surf the web and of course make cheap phone calls using the Truphone client. Apparently, I am not the only one — people love WiFi-based Internet access on their phones, according to a recent report by San Mateo, Calif.-based mobile advertising company, Admob.

They say that in November, about 8 percent of total requests were coming from WiFi networks, versus 3 percent in August. No surprise, 42 percent of iPhone requests are made from WiFi, notably higher than most other WiFi capable phones which average between 10-20 percent. I think that is because AT&T’s (s T) 3G service has the unpredictability of Lindsay Lohan’s mood that we instead opt for WiFi. It is good that AT&T splurged on Wayport, a WiFi service provider and saved us a whole lot of waiting. In UK, Nokia’s N Series are pretty popular behind iPhone and iPod Touch, the Nokia N95 and other N series phones are the leading WiFi devices.

On a worldwide basis, Nokia’s (s NOK) Symbian OS had 49 percent share of the smartphone traffic that comes to Admob servers, while Apple’s iPhone OS accounts for 20 percent of the traffic. In US, Apple’s iPhone was the king of the smart phone hill with 33 percent of the traffic followed by RIM (s RIMM) with 25 percent. Symbian OS had only 2 percent of the traffic. Google Phone (s GOOG), aka the G1 (HTC Dream) generated 15 million requests in November and already represents 7 percent of all T-Mobile traffic. Android had a 2 percent share of smartphone operating system traffic in the US, Admob says. That is a pretty rapid growth for a handset that just became available.

I just want to caution that these are numbers from a single company and its clients who use its advertising system. So one can’t really take them as a true representative of the market share. What these numbers reveal are general trends in the market and the general fortunes of certain specific devices and phones. For instance the growth in iPhone’s share of the traffic is indicative of the rising number of devices being sold in the market.

Related Post: