Currently Being ModeratedFeb 3, 2013 11:31 AM (in response to dan_clark)
The SIM card in an iPhone 4 will not fit in an iPhone 5, because the 5 uses a different sized card. A 4's SIM card will fit in a 4S, however.
All iPhones work the same so you should have no iTunes problems.
iPhone 5 shouldn't have shorter battery life, it should have equal, or even more, battery life. There have been complaints from the minority though - these are just faulty phones.
If you did want an iPhone 5 though, most carriers can give you a new SIM card which would fit the 5 with the same phone number. That's a good option.
Currently Being ModeratedFeb 3, 2013 11:33 AM (in response to dan_clark)
iPhone 4& 4S use a micro sim card, iPhone 5 uses a nano sim card.