Apple cut themselves a financially sweet deal when, back in 2007, they agreed to make AT&T the sole service provider for the iPhone:
The original Apple/AT&T revenue deal was so unfavorable to AT&T that only a half-dozen other carriers in the world would agree to Apple’s terms. Remember, Apple always prefers to take profit over market share. (source)
Today, the Wall Street Journal is reporting that Apple has reached an agreement to give a forthcoming version of the iPhone to AT&T’s arch-rival Verizon Wireless. Why would Apple suddenly change their mind? Lately, (Google’s smart phone software) Android has been outselling the iPhone. Android is carrier agnostic, which has a lot to do with its success. If this report is true, Android has now officially gotten Apple’s attention in a big way.