Why has my i phone 4 stopped charging?

[gototo]

My i phone 4 has stopped charging all of a sudden. I have tried different wall chargers, usb leads, charging from laptops and pc and no joy. The battery has gone now and it does not become visible on i tunes.
Any ideas what might have happened or how to fix would be gratefully received!

 

[Johnny]

You should go to the apple store the battery might have burnt out