I just purchased an iPhone 4 after going from a 3G to a Moto Droid (complete trash) and was just adding some contacts in manually. My question is what is the slot for iPhone number for. When I create a contact I put the name in and then in the mobile slot the number. After entering this a line appears to enter an iPhone number. Is this supposed to be used, I only know a few who do have them and don't where I should enter numbers. When I go back to a contact that I just entered a mobile number the facetime button option is there. Any help on what the whole distinction deals with would be appreciated. Whether to use mobile or iphone to slot a number in was never something I ran into in the past. Thanks.