OK here is what I want to do. I have the 3GS. Spouse has 3G. I'm getting the iPhone 4 and want to pass down my old 3GS to Spouse then sell spouse's old 3G. This is how I think I can do this so please tell me if my thinking is off anywhere. Backup my current 3GS to iTunes before I go pick up my new phone. Bring new home phone and restore from backup. Do a restore to new on my now old 3GS. Take sim card out. Go to spouse's computer and do a backup of his 3G. Take the sim out of spouse's 3G and put in my now old 3GS and plug into his itunes and restore from backup. Put in the discarded sim from my old 3GS into spouses now old 3G and do a restore to new and then remove sim and sell it without a sim. Is this all correct? Do I have to call ATT at all and let them know of the change?