The iPhone 5 is the first Apple device with armv7s processors.
Is the instruction set identical?
What about backwards compatibility? Will the iPhone 5 be able to run apps compiled for the armv6 and armv7 architectures?
AnandTech has an analysis of the new CPU: http://www.anandtech.com/show/6292/iphone-5-a6-not-a15-custom-core
The main difference is apparently that ARMv7s has VFPv4 support (but you should read the full article, it's very thorough).
The cpu is backwards compatible, it will be able to execute apps compiled for both ARMv6 and ARMv7.