iFixit published an early teardown analysis of the iPhone 4S. This initial report suggests the iPhone 4S closely resembles the iPhone 4 on the outside and the inside. The form factor is the same, the pentalobe screws are the same, and even the logic board looks similar to the CDMA iPhone.
Besides the A5 processor, the biggest difference between the 4S and the 4 is the battery, which has an extra .05 WHrs. It also has a slightly different connector which prevents you from taking the 4S battery and popping it in the iPhone 4. Hopefully, iFixit will pry off the logic board's EMI shields and discover what other exciting hardware components lurk underneath.
