I missed this article from the April 20 New York Times about how Internet players, mobile handset manufacturers and mobile operators are tackling mobile advertising. It's a quick and informative read.
On a related note ... I walked into the office today to find that email and Internet were down. I was admittedly annoyed, but without skipping a beat I fired up both my work email and Yahoo! email [using Yahoo! Go Gamma] on my mobile phone. Within 5 minutes I was able to delete the spam from both accounts and reply to a few simple requests. If I had been in Europe I would have used my 3G phone as a high-speed modem to log on to my company's email/Intranet.
Based on what I know about the US market, this is not typical behavior [yet ... although I'm confident we'll catch up to the rest of the world soon enough]. I could easily fool myself into thinking I'm an early-adopter in the mobile space. But I'm not naive enough to think that my behavior wouldn't change if I were paying for my own data plan.