According to the latest findings from iSuppli, Apple's iPhone was the top selling smartphone in the U.S. in the month of July. iSuppli stands by its earlier estimate that the iPhone will sell 4.5 million units in 2007. Take that, iPhone skeptics.That's right, the iPhone outsold smartphones from RIM, Palm, Nokia, Samsung, and Motorola. So much for Apple being an upstart. Based on these numbers, Apple is now a top player in the U.S. smartphone market.

Here is a look at iSuppli's demographics for iPhone customers:

* Approximately 57% of iPhones bought in July were purchased by U.S. consumers 35 years of age or younger. * Most iPhone buyers were men in July, with 52% of purchasers being male and 48% female. * Nearly two-thirds, or 62%, of iPhone buyers in July had a four-college degree or more education. * One quarter of consumers who bought iPhones switched to AT&T service. AT&T is the exclusive provider of service for the iPhone.

I am confused by statistic number four. If only 25% of those who bought an iPhone actually switched to AT&T, what did the other 75% do? I am sure some of these were existing AT&T customers, but were all of them existing AT&T subscribers? Did many of these customers just sell their iPhones on eBay? Or are many of them waiting for iPhoneSIMfree to hit the market? Or did they just return the iPhone after 10 days, like me? I suspect this statistic will change once the August numbers come out.

Otherwise, based on this data, the iPhone's customer base looks a lot like that of RIM's BlackBerry, i.e. well-educated, affluent professionals. So much for the iPhone as just a consumer play. If these market demos hold steady, the iPhone could well challenge the BlackBerry, especially in the prosumer market where the BlackBerry Pearl and Curve have done quite well. I have to imagine that RIM is a little worried, probably more now than they were two months ago.