The micro-SIMs used in the iPad 3G are not compatible with the iPhone 4 and the iPhone 4 micro-SIMs cannot be used in the iPad, this translates message available on the Apple UK online store website. I haven't seen what a micro-SIM looks like for the iPhone 4, but I don't know why these cards wouldn't fit together considering that a normal card can be cut and used in the iPad without any problem.
Probably this message is just a strategy of those from Apple to force buyers to purchase micro-SIMs, because theoretically these cards can work without any problem in any of the 2 devices. Anyway, when you buy an iPhone 4, you have to keep this aspect in mind so as not to be surprised if the message is really true.
