Yeah, your iPhone has access to that high-speed cellular data network. But admit it: you use Wi-Fi whenever you can, right? Why, these days I'm tempted to walk into every Starbucks I pass and log in for free Wi-Fi just because I can! 3G may beat EDGE, but Wi-Fi beats both.

Turns out we're not alone. According to a report (PDF download) released Thursday by mobile ad network AdMob, iPhone users divide their time almost evenly between cellular and Wi-Fi-based networks.

AdMob's the company that makes it easy for Web sites and (usually free) iPhone apps to embed ads. As a result, it's able to monitor where incoming requests for ads are coming from: via a cellular provider's digital network or via other IP addresses which are presumably part of a local Wi-Fi network.

AdMob says iPhones made 58 percent of their ad requests from cellular networks, with the remaining 42 percent being made on Wi-Fi networks. In comparison, the total number of Wi-Fi based ad requests on AdMob's entire network was only eight percent. Between the iPhone and the Wi-Fi-only iPod touch, Apple devices made up 79 percent of all Wi-Fi requests AdMob saw in November.

Of course, not all Internet-connected phones are Wi-Fi capable. The HTC G1, running Google's Android operating system, is--but according to AdMob, only 10 percent of the G1's ad requests came from Wi-Fi networks.

Worldwide, AdMob reported that the iPhone and iPod touch now make up nearly eight percent of all ad requests on its network, placing Apple fourth in the category behind Nokia, Motorola, Sony Ericsson, and Samsung. In the United States, Apple devices made up 12 percent of all mobile ad requests, placing the company third behind Motorola and Samsung.

In terms of overall iPhone growth, AdMob's report has some good news on that front too: worldwide ad requests from iPhones grew 52 percent between October and November. But of course, given how many iPhone apps are ad supported, there's no way to know how ad impressions equate to overall usage or overall devices in action.

[Hat tip: Gregg Keizer of Computerworld.]

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