I read where the SIM card for the 4S is different from the 3GS. That being the case how difficult will it be for me to transfer all my contact info from my old phone to my 4S? I would hate to have to manually do that.
Sync your phone with iTunes and then right click on the phone and pick backup (do this right before you setup the new phone so your latest settings/contacts/messages get saved) -- when you're setting up your new phone pick restore from backup and select your old phone's backup which will transfer over your phone settings, then it'll sync it with iTunes to transfer over your apps & stuff
Okay, so I will not have a problem taking this approach when going from an iP4 to iP4S but what is the best way to handle my SO's move from iP3GS to my old iP4? I know my iP4 is backed up but I don't remember if the iP3GS is since they both use the same Apple id.
Once I get this setup, I will sync not only her calendar but her contacts through Google to avoid this kind of problem in the future.