replace in warranty iphone with minor damage?

[jatt123]

I have a sprint iphone 4s in warranty still with minor damage. (it has a crack on top to the right of the FaceTime cam. It starts from the bottom of the headphone jack and stops to the left side of the silent switch. Its only on the front.) The screen and backside is in great shape. I been having problems with the wifi connection. I was wondering will apple replace the iphone even if it a little damage on it? Also I don't have an sprint account. Will apple saying anything about not having one? I'm afraid they will require me to activate it in store. Anyone experience these situations or similar to mine please feel free to comment here thanks!