If my iPhone doesn't work, will apple replace it?

My iPhone has stopped working:'( Can i just take it into apple and they will give me a new one or will i need the box and receipt as-well?

Depends if you are on contract with insurance they will send you out a new one but if not then i don't think so

You will need the box to prove you have baught it and that the warrenty hasn't run out.

Depends of the fault…
yes you should always keep the box etc.
might be worth going to apples site to see if the have any info