Do micros SIM cards 'hold' all your contacts on them or are they held within the phone? I'm just trying to get my head round this!! If I swap a micro SIM from a Nokia 520 (Windows) to an iPhone 4, will it take all the contacts with it?
Contacts are only held on the sim if you have set it to do so. You can move all your contacts to the sim but they only allow the contact name to be of a certain charset; Stephen Sailsbury wouldn't fit so the name might be saved as Stephen Sa. You can move your contacts to your sim via your address book.
I've just changed from a BlackBerry to a Samsung Galaxy and the guy in the shop, with the aid of a clever little device, transferred all my stuff to the new phone. S5 highly recommended.