I Just got my new 5. I am giving my wife my 4S. She currently has a 4. Besides exchanging the SIM cards what do I need to do with my old 4S and her old 4 before I make the SIM exchange?
On your wife 4 she will need to do this http://support.apple.com/kb/HT1766
then on your 4S - settings - general - reset -erase all contents and settings.
then your wife can restore the 4S from the backup she made.
Retrieving data ...