http://www.nikonchat.com/nikon-nikkor-lens-18/

Nikon Nikkor 18-55mm lens focusing ring IS LOOSE?
I have a Nikon D5000 and recently my 18-55mm lens focus ring has been randomly loose. No loose everywhere, it feels like you loose on a shaft, not the wobble of a 360, but the simple set aside. And it's making me very angry. Anyone aware of how to fix this?
I just checked my focus rings have some slack in them because they have a M / A switch to M. In the M / A mode, you can move the lens without damaging the lens motor. There is no reason to be angry about it. Nikon give you a call and ask about it. 800.NIKON-UX