Does my iphone work everywhere?

I want to buy a new iphone 4s in america but i will be moving to italy next month, will i still work or do i need a new one?

It will work.

Check to see if GSM or CDMA as iphone 5's are both, but I think 4S is one or the other and you need to make sure thats what italy has.

If you buy one from AT&T or T-mobile (which are GSM carrier, the same technology that is used in Italy, the rest of europe and the larger part of the world) and you unlock it than it will most definitely work. If you buy one from any of the other carriers (verizon, sprint… ) it won't work because they use the CDMA technology which is not widely used outside the USA and certainly not in Italy.