I have analysed the iPhone 3GS against several price dimensions, including Provider, Monthly price, and Price per GB (gigabyte) of data (as at July 2009). A separation appears between the five phone companies, charging either low monthly price, and high data costs or high monthly price and low data costs.
A Value Frontier appears, that I have graphed.
The analysis has been distributed to a few phone companies, and iPhone retailers for comment. Feel free to comment below.
The summary analysis can be found here (link). Cost $500. Free to download (Donate requested). A fuller report can be obtained by donating $500.