My iPhone 4s won't turn off?

I went to turn off my iPhone 4s and now it has been sitting there for 15 minutes just doing the spinning ball thing it does as it shuts down.

Press the home button and the turn off button then a iTunes screen will appear after that don't touch the home button and keep on pressing the turn off button and it should work

You have a bug. Hard boot it by holding down the lock button for 15 sec