Cell phones are seemingly ubiquitous in North America today. Consumers in four out of five homes have a mobile phone, and the number jumps to 91% among households headed by a Gen Yer. The vast majority of these phones subscribe to service from the small group of carriers that dominate the market. Mobile service is clearly no longer just about voice; subscribers use a wide range of data applications, including a growing number who access the Internet on their phone. RIM and Palm Treo are two of the three phone brands whose owners are the heaviest users of the mobile Internet. Which brand tops the list? Can you say "iPhone"?