Supposedly the 1st gen with fw 2.1 does (Vodafone 2v1 sim)
There are some iphones that do have dual sim cards.
N, it is not possible to convert the iPhone 4s to a dual sim.
No
Not anymore than ks to SIM Cards and the 4S's dual-antenna ability.
No sim cards are only for numbers
Yes, iPhones use a normal sim card.
The iPhone uses the micro SIM card
Yes it can be swapped. I actually swapped my razr's sim card to my iphone. Nothing happened. It works perfectly.
Iphone uses sim cards to track the user and gets all hidden information from them
Buy a SIM Card from AT&T or T-Mobile called a Micro-SIM. These will fit in the iPhone. Apple is planning on using Nano-SIM Cards which are even smaller.
Yes all iPhone have SIM cards although they are called micro sims (the gold chip only)
Sprint doesn't use SIM cards...