iPhone 5 will bring a new feature, remote computing, based on NFC (Near Field Communication) technology according to an exclusive post on Cult of Mac.
iPhone 4 uses a Micro SIM instead of a standard sized SIM and the same Micro SIM is also used in iPad. Micro SIM is not provided by cellular carriers in most countries. However, it is very easy to convert the standard SIM into a Micro SIM by cutting it carefully. You can see images here to learn how to cut the SIM for iPad and iPhone 4.