With AT&T's acquisition of T-Mobile USA (pending approval), it only makes sense for the iPhone 4 to become available on the latter. Codenamed N94, this tester "phone itself is running a test version of Apple's iOS and it includes internal Apple test apps like Radar and Apple's employee directory app." Click here for more pictures.
Additionally, the front of the white iPhone pictured looks a little different from the photos of the retail white iPhone 4 that surfaced recently - specifically, the proximity sensor has changed on the retail version.[via BGR]